Expert: John Zalewski - 6/9/2009

Question
Hello John.
Is that true that n*0=0, where n is an integer?
Now :
15*2=30 which means 30/15=2 and 30/2=15
100*4=400 which means 400/100=4 and 400/4=100
20*5=100 which means 100/20=5 and 100/5=20
2*0=0 which means 0/2=0 and 0/0=2(????)
Isn't the result of integer times zero is undefined?
Please explain. Thanks.

Answer
Hello, Joe.

To my knowledge, division by 0 is still a very confusing concept, even for mathematicians. Some say that 0/0 = 0; others say that the answer is undefined; even others say that the answer is infinite.

n(0) does equal 0, because you are either taking 0 groups of n, or n groups of 0, which of course is 0 in both instances.

My hand-held calculator gives 0/0 as equaling "E" (error), and my computer calculator gives the answer as undefined. I cannot help further. I am sorry.

Regards,
John