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commutative

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Multiplication and repeated addition 2016-11-23
Anandmay pose la question :
Hello I was looking closely at early arithmetic where I found how we discovered properties of Arithmetic. Like:2 x 3 = 3 x 2. This can be proved by considering a 2-D figure(actually,quadrilateral) having length consisting of 2 boxes of 1-by-1 dimensions and breadth of 3 boxes of the same dimensions. Now,consider it again,but,this time,length of 3,and breadth of 2 of such 1 by 1 boxes. We now notice that we can fit the 2 types of rectangles formed on each other precisely. So the multiplicative property of commutativity is true for all natural numbers as we can generalize the result(in our mind,for self satisfaction).

Now,can you find me a nice satisfactory reason of why a fraction times a natural number equals the number times the fraction? I mean, for example,i can understand the meaning of 3 x 2/3 to be three times 2-3rd,that is, 2/3+2/3+2/3.Fair enough. But here is the problem:By definition and actual meaning of multiplication, a x b means the repeated sum of b,done 'a' times. So what is the meaning of doing 2/3 x 3?The repeated addition of 3 how many times??2/3 times??Not making sense,right?And even we have not proved yet the commutative property of numbers INCLUDING fractions.So how can we resolve this problem and make these things meaningful?
Thanks

Penny Nom lui répond.
Associative or commutative? 2007-08-24
Terry pose la question :
5*(7*2)=(7*5)*2 Is this associative property or commutative ??? Both?
Penny Nom lui répond.
A binary operation 2007-07-31
sofia pose la question :
Prove that if * is associative and commutative binary operation on a set S, then (a*b)*(c*d) = [(d*c)*a]*b

for all a,b,c,d element in S. Assume the associative Law only for triples as in the definition that is, assume only (x*y)*z = x*(y*z) for all x,y,z element in S.

Penny Nom lui répond.
Binary operations 2007-07-30
jim pose la question :
prove or disprove:

Every binary operation on a set consisting of a single element is both commutative and associative.


Penny Nom lui répond.
A commutative subgroup 2007-05-03
moulipriya pose la question :
If H be a commutative subgroup of a group G. Then can we say that G is also commutative?
Penny Nom lui répond.
Definitions 1997-09-08
SohoGirl13 pose la question :
I am an 8th grader. my e-mail address is SohoGirl13@aol.com. I have a question: what are the associative, communitive, and distributive properties?
Harley Weston lui répond.
 
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