







Gauss' Addition of whole numbers. 
20180430 

Brad pose la question : I found this on your site. Question: what is the sum of the first 100 whole numbers??
Is there a different formula if the numbers begin at a number other than one? For example
What is the series I want to add is goes from 7  53? Harley Weston lui répond. 





An arithmetic sequence 
20171130 

yo pose la question : x; 2x+1; 11 are three consecutive terms of an arithmetic sequence.calculate x Penny Nom lui répond. 





An arithmetic sequence 
20170717 

abbi pose la question : hi there im a student in 11 grade
ive been trying to do this task but i have no idea how to do it
the question is
Find the common difference and the n^th term of the arithmetic sequence if the first term is 4 and the twentieth sum of the terms is 1030 Penny Nom lui répond. 





Why does 10x10x10 give 1,000.0000000000001? 
20170412 

Randolph pose la question : Hi, On your calculator I found that a box 10 by 10 by 10 inches has a volume of 1,000.0000000000001 cubic inches. Can you explain the numeral 1 thirteen places past the decimal? Thanks, Randy Penny Nom lui répond. 





Addition and subtraction base 5 
20170129 

BABAWALE pose la question : Simplify 342five +132five223five Penny Nom lui répond. 





Which term of this sequence has value 8? 
20160720 

Lauren pose la question : Hi there
Which term in the sequence 2; 5/3; 4/3 ; 1; ... has a value of 8.
Since term 2 and 3 of this sequence contain fractions which can be converted to recurring decimals. What is the best way to work out the common difference here.
I do however understand that to work out the nth term of an arithmetic series, the following formula Tn = a + (n1)d. In this series a = 2 Penny Nom lui répond. 





Calendar arithmetic 
20160214 

Jenalee pose la question : January 1, 2001 is Julian Day 2 451 911 (the number of days that have passed since Day 0, January 1, 4713 BC).
If Julian Day 0 was a Monday, what day of the week was January 1, 2001? Victoria West lui répond. 





A sequence 
20160105 

Mia pose la question : the next three terms in each sequence. 0.4, 0.54, 0.68, 0.82, Penny Nom lui répond. 





Subtraction base 5 
20150829 

nakita pose la question : can u explain the quinary subtraction ...
(3000) (2342) all the numbers are in quinary number system Penny Nom lui répond. 





1 + 2 + 3 + ... + (2n  1) 
20150101 

Brian pose la question : Hi Maths Central
My wife presented me with a query which may have a simple answer, but one that I can’t deduce or explain.
Take the string of numbers, n=1,2,3,4,5…
It seems that n(2n1) = Sum((1…..(2n1))
e.g. for n=5, both 5 x 9 and Sum(1….9) equal 45, and so on for other values of n.
Could you please provide an explanation? Does it have an underlying reason and a name?
Look forward to your response.
Brian Penny Nom lui répond. 





An arithmetic progression 
20141119 

Gbenga pose la question : In an A.P the difference between 8th and 4th term is 20. The 8th term is 1\2 times the 4th term . Find arithmetic progression.. Penny Nom lui répond. 





The sum of the first 50 terms of an arithmetic progression 
20140726 

Joshua pose la question : Hello ...my is Joshua...I'm a grade 11 student...I got a question
Calculate the sum of the first 50 terms of an arithmetic progression: 112:98:84 Penny Nom lui répond. 





An arithmetic progression 
20140331 

Japheth pose la question : The 3rd term of an A.P is 10 more than the first term while the fifth term is 15 more than the second term. Find the first term? Penny Nom lui répond. 





9,4,6,8,3,... 
20140331 

Alynna pose la question : You are given the following pattern: 9,4,6,8,3,...
Create a formula for the nth figure.
I have trouble finding the formula, I need help trying to find it. Penny Nom lui répond. 





An arithmetic sequence 
20140320 

Xabiso pose la question : The 10th term of an arithmetic sequence is 28 and the 7th term is 19. Calculate the common difference and the first term of the sequence. Penny Nom lui répond. 





An arithmetic sequence 
20140106 

paris pose la question : find the twentyfifth term of an arithmetic sequence whose first term is 12 and whose common difference is 6 Penny Nom lui répond. 





Base 5 arithmetic 
20131127 

samuel pose la question : Good day sir, please i don't understand when you say 4x4=13 in base five? In fact, am always having difficulties in addition, subtraction, division and multiplication of number in the same base other than base ten. Please can you give me one example each with details explainations? Penny Nom lui répond. 





Base 5 arithmetic 
20131012 

Obassy pose la question : (4 2 4 3)(1 3 x 4)=( Y 3 4 4),find the value of x and y in the subtraction above carried in base five? Penny Nom lui répond. 





An Arithmetic Progression 
20131008 

collins pose la question : In an A.P. the difference between the 8th and 4th term is 20 and the 8th is one and half times the 4th term... what is the common difference and the first term Penny Nom lui répond. 





Group the addends so that you can add mentally 
20131001 

monica pose la question : the questions in the homework says change the order or group the addends so that you can add mentally ,find the sum and tell which property you used
120+37+280 and 25+25+30 Penny Nom lui répond. 





The sum of all whole numbers from 1 to X 
20130906 

Tim pose la question : How do I develop a rule for the sum of all whole numbers from 1 to X when I have no idea how to do this Penny Nom lui répond. 





An arithmetic progression 
20130706 

ashok pose la question : the 4th and 10th term a.p respectively 7 and 19 find its 15th term..... Penny Nom lui répond. 





A messy arithmetic expression 
20130224 

niiaryee pose la question : (((((5^2*4^3)1/5+9^3/3)+(25+(4*5)/15)^210)/10/2)3))))) Penny Nom lui répond. 





An arithmetic progression 
20130206 

loberto pose la question : the 3rd term of an a.p is 10more than the 1st term,while the 5th term is 15more than the 2nd term,find the sum of the 8th and 15th terms of the a.p if the 7th term is 7times the 1st term Penny Nom lui répond. 





Mod versus Rem in Turing 
20130101 

Eric pose la question : I am a teacher teaching computer science using Turing. I am having
difficulty understanding why one would use the mod operator versus the rem
remainder operator.
Mod seems to make the resulting sign depend on the sign of the divisor,
whereas rem makes the resulting sign depend on the dividend.
Examples:
11 mod 5 = 1 and 11 rem 5 =1
11 mod 5 = 4 and 11 rem 5 = 1
11 mod 5 = 4 and 11 rem 5 =1
11 mod 5 = 1 and 11 rem 5 = 1
What I can't understand is why this would matter. For example, 11 / 5 =
2.2 and 11 / 5 = 2.2 get the same result.
So how is a remainder dependent on the sign of one of the parts?
What benefit would using one over the other have?
Any insight would be most helpful!
Eric Harley Weston lui répond. 





An arithmetic progression 
20120822 

A student pose la question : the 3rd term of an A.PPP is 10 more than the first term while the 5th term is 15 more than the second.find the sum of the 8th and 15th terms if the 7th term is 7 times the first term. Penny Nom lui répond. 





6/2(1+2)=? 
20120221 

boyong pose la question : 6/2(1+2)=? Harley Weston lui répond. 





An arithmetic expression 
20120105 

Jennifer pose la question : 1.8 + 3.2 / 0.4  4.375 x 0.2 Penny Nom lui répond. 





Mean and Average 
20120103 

john pose la question : what is the difference between average and mean Robert Dawson lui répond. 





The 3rd term of an A.P is 10 more than the first term 
20111129 

Olaniyan pose la question : the 3rd term of an A.P is 10 more than the first term while the fifth term is 15 more than the second term. Find the sum of the 8th and 15th terms of the A.P if the if the 7th term is 7 times the first term. Penny Nom lui répond. 





An arithmetic expression 
20111128 

Muhmmad pose la question : 2/5*3/71/6*3/2+1/14*2/5 Penny Nom lui répond. 





Three consecutive terms of an arithmetic sequence 
20111030 

Juliette pose la question : Find X when x, 1/2x + 7, 3x 1 are consecutive terms of an arithmetic sequence. Penny Nom lui répond. 





Modular arithmetic 
20111030 

Kim pose la question : Hello,
I am editing a resource for students, and I think some of the answers may be incorrect.
The text I was given and my questions are in the attachment.
Any help you could give would be appreciated.
Thanks,
Kim Harley Weston lui répond. 





 16 x 6 / 2 
20110909 

Nadiyah pose la question : i dont understand how to answer this question ;
 16 x 6 / 2
i still dont understand it with bedmas
/ = divison
please help! Penny Nom lui répond. 





(x^3 + 11x) is divisible by 6 
20100624 

PT pose la question : Given that x is a nonzero integer,
how do you show that for all values of x,
(x3 + 11x) is divisible by 6?
I know it works but how do I answer the "all values of x" part?
Thanks in advance! Robert Dawson lui répond. 





4 + 10 + · · · + (6n − 2) 
20100421 

Lan pose la question : Find the sum 4 + 10 + · · · + (6n − 2). The answer is 3(n^2) + n. How? Penny Nom lui répond. 





(24x3)+(7x8)(20/5)+(4x7) 
20091201 

Marilyn pose la question : (24x3)+(7x8)(20/5)+(4x7)
Thought I had the answer but the form says no. Could you solve it for me please. Penny Nom lui répond. 





24 feet of pipe in 3 pieces 
20091009 

Sam pose la question : I had a carpenter being a smarty pants with me. Question: I have a 20ft piece of pipe. I need three equal lengths cut. What is the measurement of each cut? He told me the answer right away because he knows the measuring tape like the back of his hand. The answer is 6'8". Is there an equation I can use to get the answer quicker than him looking at his tape measure? Penny Nom lui répond. 





How many terms are there in this sequence? 
20090928 

tabby pose la question : How many terms are there in this sequence?
5,1,3,...,111 Penny Nom lui répond. 





Arithmetic Sum & Sequence 
20090901 

Alice pose la question : Find the 24th term of this sequence
6.8,8.0,9.2...
Find the sum of the first 21 terms Janice Cotcher lui répond. 





Subtraction base 5 
20090809 

Nikki pose la question : can you help me how to do subtraction in base 5 notation. example is 3434  51?
how do you do this in base 5?
can you please explain how you do this & the answer as i have no idea.
Thank you kindly
Nikki Harley Weston lui répond. 





Finding the Common Difference and Number of Terms of an Arithmetic Sequence 
20090724 

Juan pose la question : In an arithmetic sequence, the first term is 2, the fourth term is 16 and the nth
term is 11,998
A. What is the common difference?
B. What is the value of n. Janice Cotcher lui répond. 





WHAT IS 8+4(227) 
20090505 

ROB pose la question : WHAT IS 8+4(227)= Penny Nom lui répond. 





The middle term of an arithmetic sequence 
20081215 

Leigh pose la question : Find the sum of the first fifteen terms of an arithmetic series if the middle term is 92 Penny Nom lui répond. 





An arithmetic series 
20081017 

Laura pose la question : In an arithmetic series 5+9+13+...+tn has a sum of 945. How many terms does the series have?
What formula do I use? Penny Nom lui répond. 





Bags of pennies 
20081011 

paul pose la question : jenny divided 15 pennies among 4 money bags.she could then pay any amount from 1p to 15p just by giving bags.how many pennies did jenny put in each bag? Penny Nom and Victoria West lui répond. 





Four weights 
20080825 

Darla pose la question : A balance had known weights of 1/2 lb, 1/4 lb, 1/8 lb, and 1 oz. Edna's object weighted 2 oz. more than Paul's. Each used 3 known weights to weight his or her object. which know weights did each use? Penny Nom lui répond. 





The product of the digits of a four digit number 
20080726 

Pete pose la question : I am a student preparing for a competition and this was one of the prep problems: The product of the digits of a four digit number is 6x5x4x3x2x1. how many such numbers are there with this property? Stephen La Rocque lui répond. 





Remainders 
20080630 

vivek pose la question : what is the remainder when 2050*2071*2095 is divided by 23 ?
this question needs to be done in as less time as possible. Penny Nom lui répond. 





1?2?3?4 = 7 
20080425 

john pose la question : 1 2 3 4 = 7
The numbers have to stay in order of 1234 and when added,subtracted,multiplied or divided they have to equal 7. Stephen La Rocque lui répond. 





1+15=20? 
20080425 

MUBARAK pose la question : 1+15=20? Penny Nom lui répond. 





Base 5 arithmetic 
20080306 

Jana pose la question : Hello, my name is Jana, i have asked a question here previously about how to count in base5. I am happy now because i can convert any number now and it is very easy for me. The only thing i am having trouble with is understanding how to do a maths sum or times base5 numbers. it is just a bit hard for me. So do you think you could explain how to do a sum in base5 and how to do a multiplication sum. Please help...Thankyou Jana!! Harley Weston lui répond. 





An arithmetic expression 
20080305 

Kasani pose la question : evaluate the expression: 2^1[14  4(6)]  (7  3) Penny Nom lui répond. 





10  3 + 2 
20080221 

Amrit pose la question : what 103+2
is it 5 or 9 Penny Nom lui répond. 





The nth term 
20071018 

shannon pose la question : Ok , what i am having problems with is the nth term. I get how the numbers come together, but i am having trouble with finding the nth term. Penny Nom lui répond. 





Solving arithmetic problems in the right order (BEDMAS) 
20071005 

Kim pose la question : 3+4x2(10 divided by 5)= what? Penny Nom lui répond. 





The nth term 
20070909 

Conor pose la question : Please can you help me with this question on the subject of the Nth term.
3.5, 5, 6.5, 8, 9.5
5.1, 7.2, 9.3, 11.4... Penny Nom lui répond. 





2(83)+2^2 
20070730 

Nikki pose la question : 2(83)+2² Penny Nom lui répond. 





How many terms in this sequence? 
20070611 

Jesse pose la question : How do I find how many terms are in the sequence? 51, 48, 45, ...., 75 Stephen La Rocque and Penny Nom lui répond. 





Arithmetic means and geometric means 
20070404 

Dani pose la question : Hi!
I was just wondering why the arithmetic mean of sets of numbers is larger than the mean proportional of the same numbers?
Thanks!
Dani Haley Ess lui répond. 





Arithmetic Series 
20070218 

Krista pose la question : Question The sum of the first 4 terms of an arithmetic series is 8 and the sum of the first 5 terms is 500. Determine the sum of the 3 terms. Stephen La Rocque lui répond. 





5,8,11,14,17 
20070118 

Mairead pose la question : the sequence i was given was 5,8,11,14,17 what is the nth term and what is the 10th term ? Paul Betts lui répond. 





An arithmetic series 
20061128 

Jillian pose la question : Find the sum of 21 terms of an arithmetic series that has an eleventh term equal to 30. Penny Nom lui répond. 





Arithmetic with base 2 
20061126 

Yuva pose la question : can we do arithmetic ,base 2. If yes, how and if not, why. Stephen La Rocque lui répond. 





The sum of 2000 consecutive integers is 1000 
20061029 

Matias pose la question : if the sum of 2000 consecutive integers is 1000, then the sum digits of the greatest of these 2000 integers is? Penny Nom lui répond. 





Squaring numbers 
20061008 

Timothy pose la question : did anyone ever try to teach that the easiest way to find the next square in a group of numbers is to add the next odd number in the sequence. for example: 1 squared is 1, 2 squared is 4,difference of 3.the next odd number is 5 so the next square would be 4 +5 or 9 Paul Betts and Penny Nom lui répond. 





what is 8+(2)(5)/4(1)4(2+3) 
20060908 

Jordan pose la question : what is 8+(2)(5)/4(1)4(2+3) Paul Betts lui répond. 





Adding consecutive numbers 
20060426 

Lisa pose la question : When I have a total that is the sum of consecutive numbers, how do I figure out what the numbers are?
Stephen La Rocque lui répond. 





Arithmetic and Geometric Sequences 
20060419 

Skye pose la question : If the 1st, 4th, and 8th terms of an arithmetic sequence are consecutive terms in a geometric sequence, find the common ratio of the geometric sequence. Stephen La Rocque lui répond. 





Arithmetic Sums 
20060412 

Angel pose la question : (a) In a particular arithmetic sequence, u6 = 344.5 and u20 = 88.3. Find S28.
(b) In a particular arithmetic series, S10 = 495 and S15 = 1005. Express S15 in sigma notation. Stephen La Rocque lui répond. 





(175)/3x2 
20060226 

A student pose la question : can you help me answer this question (175)/3x2 Penny Nom lui répond. 





Arithmetic progressions 
20060131 

A student pose la question : 1)the sum to n terms of a particular series is given by S_{n}=17n3n^{2}
a)find an expression for the n term of the series
b)show that the series is an arithmetic progression
2)a particular arithmetic progression has a positive common difference and is such that for any three adjacent terms ,three times the sum of their squares exceeds the square of their sum is 375.Find the common difference
Penny Nom lui répond. 





For what divisors can you get a remainder of 8? 
20060106 

Thelma pose la question : When dividing a 3 digit number by a 1 digit number, for what divisors can you get a remainder of 8? Penny Nom lui répond. 





(5 + 10) x 2  10 = 
20051205 

Jessica pose la question : (5 + 10) x 2  10 = Penny Nom lui répond. 





An Arithmetic sequence 
20051201 

Aana pose la question :
The first term in an arihmetic series is 25 and the 3rd term is 19. Find the number of terms in the series if its is 82.
Here's what I did to find d
a+2d=19; 25+2d= 19 ;1925=2d d=6/2=3
This is where I'm stuck. Can you please provide me with some guidance.
Penny Nom lui répond. 





Two groups that have equal sums 
20050930 

Anita pose la question : using the numbers 1, 2, 3, 4, 5, 6, 7,and 8. how do we divide them into two groups so that they have equal sums? Penny lui répond. 





BEDMAS 
20050901 

A student pose la question : I am a student and am wondering about the answer to this question.
56/2(31)
is the answer 7?
Harley Weston lui répond. 





Three prime numbers p,q and r, all greater than 3, form an arithmetic progression: 
20050718 

Ladis pose la question : Three prime numbers p,q and r, all greater than 3, form an arithmetic progression: p=p, q=p+d and r= p+2d. Prove that d is divisible by 6. Chris Fisher lui répond. 





An arithmetic progression 
20041224 

A student pose la question : the 4th and 5th term of an arithmetic progration 47 and 52 respactively find
a)d
b)a1
c)a50 Penny Nom lui répond. 





Bedmas 
20041030 

Gina pose la question : I am just curious whether Bedmas would be used in the following question as it is not in the typical Bedmas format.
Multiply 12 x 24
Add 26
Divide by 2
Subtract 7
Would we go about doing it in the sequence it is given or in Bedmas ? Penny Nom lui répond. 





1+3+5+...+(2n+1) 
20040910 

Emma pose la question : Prove that 1+3+5+...+(2n+1)= (n+1)^{2} Penny Nom lui répond. 





Half way between 
20040908 

Ben pose la question : Find the number halfway between the number shown
751,843 Penny Nom lui répond. 





The sum of some positive integers 
20040607 

A student pose la question : Find the sum of all positive integers not greater than 10000 that are divisible by neither 3 nor 7. Penny Nom lui répond. 





The sum of 4,0,4..., 156 
20040428 

Christina pose la question : find the requested sum of the arithmetic sequence
4,0,4..., 156 Penny Nom lui répond. 





(3x50)+20/5=? 
20040403 

A student pose la question : what is the answer to:
(3x50)+20/5=? Penny Nom lui répond. 





Arithmetic in bases other than 10 
20031022 

Kim pose la question : how do you add, subtract, multiply and devide in base 3, base 5, etc? Penny Nom lui répond. 





1 + 1 = 10 
20030917 

David pose la question : could you please explain to me how 1+1=10 thanks Penny Nom lui répond. 





Converting from base 10 to base 5 
20030910 

Susy pose la question :
My son, who is 9 in grade 5 has been asked to convert base 10 numerals into base 5. His first question of: 24(10) he has calculated to be 4x5 + 4x1 = 44 (5) The next question however is the tricky one.Ý We know the answer is supposed to be 100 but we find it difficult to get this in the way he understands it. 25 (10) = _________________ 100 (5) Can you help us figure out how we reach the answer. Claude Tardif and Penny Nom lui répond. 





38 minus 10 plus 12 divided by 4 times 16 
20030423 

James pose la question : please help me work this math problem 38 minus 10 plus 12 divided by 4 times 16 Harley Weston lui répond. 





Chopping trees 
20030419 

Tamara pose la question :
The master needs some of the trees (twenty, to be exact) at the back of his spooky old mansion cleared to make way for a new evil laboratory, so he decides to send some his slaves to do the work for him. He initially sends out four of his men, armed with axes, to chop the trees down. Due to the fact he is very impatient, every ten minutes he sends out another man to help with the work. Assuming that it takes one man 30 minutes to chop down 1/3 of a tree, how long till all twenty trees are chopped down? Penny Nom lui répond. 





How many hits? 
20030406 

Jack pose la question :
My name is Jack. I'm a uncle. Student is in the 5th grade email is above. If a baseball player at sping training had a good season with the following: one seventh of his hits were doubles. 12.5% of his hits were home runs. But didn't have any triples. How many hits did he have? Can you give me an explanation of you solved the problem. Penny Nom lui répond. 





Finite differences 
20030210 

Jenny pose la question :
I need to find a formula that will work with any number. I am finding the volume of a 3d cross shape. Here are my results so far:
Term Number 0 1 2 3 4 5
nth term 1 7 25 63 129 231
1rst diff 6 18 38 66 102
2nd diff 12 20 28 36
3rd diff 8 8 8
I can't seem to find a formula that will work with any number. Any help would be much appreciated. Penny Nom lui répond. 





The sum of the first 1000 even integers 
20030206 

Jill pose la question : What is the sum of the first 1000 even integers? Paul Betts lui répond. 





Arithmitic sequence 
20030201 

A student pose la question : I am having problems solving this arithmetic sequence... 1, 5, 10, ___, 50, 1.00, ___, 10.00, ... I believe the answers to be 25 and 5.00 but I can't figure why. Claude Tardif lui répond. 





1+2+3+...+500 
20030131 

Brian pose la question : What is the sum of the numbers from 1 to 500 inclusive? Paul Betts lui répond. 





5x(2)32/8 
20030113 

A student pose la question : I'm having problems solving this question: 5x(2)32/8 Penny Nom lui répond. 





Integer arithmetic 
20021205 

A student pose la question : Would you please help me with a question?
I am just learning about integers. Can you show me in a way I might understand....My teacher can tell me what is required to do the math, but it just doesn't make sence to me.
(+4)  (3) =+7
Why is the answer not +1 Diane Hanson lui répond. 





Chisanbop 
20021107 

Paul pose la question : I'm trying to find the book/books that explain this system? I have one small book that explains the very beginning of the system, but covers only about 10 to 20%. I'v tried several book sellers and have had no luck. Diane Hanson lui répond. 





Sums of evens 
20020914 

Rosa pose la question : How do I find a geometric way to easily compute sums of consecutive even numbers 2 + 4 + 6 + .... Leeanne Boehm and Harley Weston lui répond. 





7+8+9+...+1000 
20020911 

Shirley pose la question : My question is what is the formula for adding up numbers when you don't start with number 1? For example 3 + 4 + 5 + 6 = 18. But how could you arrive at the answer without adding all the numbers? Penny Nom lui répond. 





3810+12divided by4multiplied by 16 
20020830 

Brenda pose la question : my math question is as follows: 3810+12divided by4multiplied by 16=? Penny Nom lui répond. 





Order of operations 
20020718 

Danna pose la question : I would like to know how to solve this type of problem; I already have the answer. Problem: 2 [5 (4 + 6)  2] = 96 Also, what do you call this type of problem? Thanks a lot. Penny Nom lui répond. 





8/13*26/27 
20020501 

Arias pose la question : 8/13*26/27= Penny Nom lui répond. 





Arithmetic progressions 
20020424 

David pose la question : I have been searching everywhere for the formula to mathamatical progression. Penny Nom lui répond. 





Take It! 
20020403 

Bryan pose la question : You are playing Take It! for $180,00 with a total stranger. There are 180 identical balls in a big vase. Each player in his turn, reaches into the vase and pulls out 1,5,or8 balls. These balls are discarded. The player who takes the last ball from the vase wins the $180,000. A flip of the coin determines that you will go first. Are you glad? How many will you take out on the first move, and how will you proceed to win the prize? Claude Tardif lui répond. 





Making 24 
20020117 

Renee pose la question : My 4th grade daughter and I need to find a simple math sentence using 5, 5, 3, & 7 to equal 24. You can add, subtract, divide or multiple. Penny Nom lui répond. 





Papy's Computer 
20020111 

MaryAnne pose la question : My secondgrade son brought home a fun math worksheet which involved calculating sums using "Papy's Computer." I had never heard of this before and found it to be quite interesting. Each digit in a decimal number is represented by a 2x2 grid. Each grid square corresponds to one of the numbers 1,2,4, or 8. Harley Weston lui répond. 





Painting walls 
20011212 

Rizwan pose la question : 3 sixth graders painted 4 walls in 3.5hrs. At that rate, how many walls would they paint in 7 hrs. Penny Nom lui répond. 





Recalling the basic facts 
20011212 

A parent pose la question : My son is in 4th grade and is a very bright student. He is in the gifted program and makes straight A's on his report card and has through out school so far. My question is how can I teach him to memorize his basic math facts? He does well in math, but when he is placed in a times situation for completing math fact sheets he freezes up. He can not recall the basic facts when questioned at any other time either. He will calculate the answer in his head, like 6 + 3, but he can't just come out with the answer quickly. How can I help him? Claude Tardif lui répond. 





Negative times negative is positive 
20011026 

Mary pose la question : I have a question about adding and multiplying positive and negative numbers. When we add two negative numbers the answer is negative BUT when we multiply two negative numbers the answer is positive. I don't understand. Why? Penny Nom lui répond. 





Arithmetic sequences 
20010910 

Rachel pose la question : I can't seem to figure out a problem that deals with arithmetic sequencing. This is the question: The 5th term in an arithmetic sequence is 1/2, and the 20th term is 7/8. Find the first three terms of the sequence. I attempted this problem with the formula: An = a + (n1)d (where the n represents the nth term, a is the first term, and d represents the common difference) I keep getting 9.5 for the first number, and then 3/120 as the common difference between the numbers. But as I have figured it, the sequence is getting greater and greater, and my data does not go with the terms given. Penny Nom lui répond. 





Geometric and arithmetic sequences 
20010126 

Garry pose la question : what are the equations for geometric and arithmetic sequences? also, what are the equations for finding the sums of those series? Leeanne Boehm and Penny Nom lui répond. 





Order of operations 
20001126 

Margaret Pratt pose la question : My daughter has a math question and I am afraid I am of no help. Can you help? 2x5/2+15= She arrives at 8 as the answer and has been told this is incorrect. Any help you can give would be appreciated. Penny Nom lui répond. 





Arithmetic in base 5 
20000920 

Lesley Emerson pose la question : my daughter is 9 and has been aske to solve the following in base 5 3+2 4+10 . . . Penny Nom lui répond. 





Order of operations 
20000919 

Nicole pose la question : the problem is, 4x818 divided by 6= do you solve this by doing 4x8=32 then by dividing 18by 6= 3, then subtracting 3 from 32 = 29? If not what is the order of operation? Penny Nom lui répond. 





7     77 
20000913 

Peter pose la question : Does anyone know how to solve the following: 7 _ _ _ _ 77 ? I have to find the missing values. Chris Fisher and Walter Whiteley lui répond. 





How many 17's and 19's total 1000? 
20000907 

Jonathan pose la question : My question is: what 2 numbers would multiply 17 and 19 for a total of 1000. The numbers should not contain any decimal. Penny Nom lui répond. 





The sum of the squares of 13 consecutive positive integers 
20000825 

Wallace pose la question : Prove that it is not possible to have the sum of the squares of 13 consecutive positive integers be a square. Harley Weston lui répond. 





Find the next term 
20000812 

Ashley pose la question : 8,27,64 I need the next three numbers & I can't figure it out. I have worked on this all day. Penny Nom lui répond. 





Why does division start from the left? 
20000524 

Salil Dave pose la question : Addition, subtraction and multiplications start with right most digit and proceed left, but division starts from leftmost digits and goes right ... why? Harley Weston lui répond. 





The number of seats in an auditorium 
20000516 

David Evaska pose la question : There are 10 students in the first row of seats in an auditorium 12 in the second 14 in the third and 2 additional in each seat. The total number of rows is 40. I know the answer is 1960 can you please show me the formula step by step. Penny Nom lui répond. 





Finding a formula 
20000505 

Erica Hildebrandt pose la question : If a farmer has a field and his plots are laid out in the following grid where each # represents a plot: 4  5  12  13  20  3  6  11  14  19  2  7  10  15  18  1  8  9  16  17  Of course the plot numbers aren't meaningful as I have described above. In fact they may not be numbers at all. The only constants I have are the total number of rows and columns. Using the total number of rows and columns and my current position row and column, how can I write a formula that tells me column 3 row 3 = 10, column 4 row 2 = 14, etc. I can see the pattern but can't quite get the formula. I believe I will need 2 different formulas one for even and one for odd rows. Paul Betts and Penny Nom lui répond. 





Adding fractions 
20000423 

A grade 6 student pose la question : In adding fractions, how do I rewrite the fractions so that the denominators are equal? The problem is 3/4 + 1/6 = The other problem is 11/18 + 4/9 = Penny Nom lui répond. 





Borrowing 
20000417 

A college student pose la question : How would you explain borrowing to an elementary school student? Penny Nom lui répond. 





Starmultiplication 
20000407 

Greg Potts pose la question : I have this question to answer and I don't know where to start. 1*9=0, 9*8=72 and 2*8=9, then 9*9 =? Penny Nom lui répond. 





A negative times a negative 
20000229 

Michael J. Butler pose la question : I have reviewed the answer in relation to the question of why (3)x(2)=6; however, I am still not able to properly explain the reasoning to my son, Jonathan, who is in grade 7. I want him to understand the reason for the rule that the multiplication or division of two negative numbers equals a positive number. Can you help? Chris Fisher lui répond. 





Compatible numbers 
20000127 

Angie pose la question : Use compatible numbers to estimate each product and quotient. 23*1/2 1/3*11 Penny Nom lui répond. 





Order of operations 
20000116 

Dorothy pose la question : I was wondering if you could tell me where I can get some info. on how to solve the following problem. I was given the answer but I don't know how it is solved. 4+2x(6x2)5=23 Penny Nom lui répond. 





Four fours 
19990909 

Roger pose la question : I need help with a math problem my child asked me about I guess in her 7th grade math class they were told to come up with a answer from 110 only using four 4's and she got stuck on the problem that needs to be equal to ten, she asked me and I couldn't help her it's sad so if you could give me the problem and and answer so i could explain it to her I would really appreciate it. Penny Nom lui répond. 





A double negative 
19990901 

Dennis pose la question : If b = 2 what does b = ? As in (a + 8.5)  [(b) + c] a = 1.5, c = 1.7 Penny Nom lui répond. 





Division by a negative 
19990819 

Sangeeta B. pose la question : 56/8 Penny Nom lui répond. 





A Weighty Problem 
19990617 

A parent pose la question : When using a balance scale, weights can be placed on either side of the scale. For example, if a 10 pound weight provides a counter balance to an object and a 7 pound weight, then the object must weigh 3 pounds. What four weights can be used to weigh objects of 1, 2, 3 ... 38, 39, 40 pounds? Penny Nom lui répond. 





Base 2 to Base 10, conversion, convert 
19990508 

Larry Bader pose la question : 10100011_{2} is the same as what number in Base ten? a. 83 b. 128 c. 93 d. 326 e. 163 Penny Nom lui répond. 





Roman Numerals 
19990429 

Michelle Jenkinson pose la question : Someone proposed this question to me and I do not know the answer, so I was wondering if you could help. How, using Roman Numeral, did people add, subtract, multiply, and divide with no zero or negative numbers? Penny Nom lui répond. 





Divisibility by 9 
19990221 

Razzi pose la question : I've been having a hard time trying to solve the following problem and I was wondering if you could help me. For any positive integer a let S(a) be the sum of its digits. Prove that a is divisible by 9 if and only if there exist a positive integer b such that S(a)=S(b)=S(a+b). Chris Fisher and Harley Weston lui répond. 





Modular Arithmetic 
19990204 

Leslie Kupper pose la question : I am trying to do a project on modular arithmetic. I was wondering if there were any websites that include a sample lesson plan on modular arithmetic for any grade level. Let me know where and how to find them. Thanks. Harley Weston lui répond. 





Arithmetic Progressions 
19981112 

Gerry Boser pose la question : It has been years since I was in school and I can't remember if there is a formula for the following problem: If you deposit $1.00 on the first day of the month, $2.00 on the second day, $3.00 on the third day . . $31.00 on the last day of the month, how much do you have in the bank? Now will this formula also work if it was, $0.25 (then day two you would deposit 2x $0.25 or $0.50, day three you would deposit 3x $0.25, $0.75. . . ). Will it work with any denomination?? Thank you for your time. I promise I'll write this one down for future reference. . . Penny Nom lui répond. 





Dividing a Class 
19981001 

Tom Barker pose la question : My eighth grade niece called with the following homework problem: A teacher wanted to divide her class into equally numbered groups. She tried to divide the class into groups of two, but was one student short. She tried to divide the class into groups of five, but was one student short. She tried to divide the class into groups of seven and was successful. What is the least number of students that were in her class? I know the answer is 49, but don't know how to prove it. I must be getting old if I can't solve eighth grade math problems. Your assistance would be appreciated. Penny Nom lui répond. 





Sequences and series 
19980527 

Michael Le Francois pose la question : The sum of the first ten terms of an arithmetic series is 100 and the first term is 1. Find the 10th term. The common ratio in a certain geometric sequence is r=0.2 and the sum of the first four terms is 1248 find the first term. Penny Nom lui répond. 





Clock Arithmetic. 
19980309 

Joann Dixon pose la question : What is clock mathematics? Patrick Maidorn lui répond. 





Integer Problems. 
19970915 

Eric Kowalsky pose la question : I have some intergers I can't solve. Please help me solve them! Please show me how you got the answer. 5(4)[3(6)+(3)4(2(4)7)]+3(8)=
 2[73(4)+52(1)]+3(6+8)=
 4[6(27)5(7+2)]=
 7(4)2[3(4+6)+6(73(4))]
P.S. Thank you very much. Harley Weston lui répond. 

