Question

Explain how you know that 45 divided 0 cannot be done.

Answer 1

I'll give you what I know that is an undefined problem.

Answer 2

You can't divide something by nothing.

Answer 3

one has to understand what division really is

e.g. 12/3 = ??

12-3 = 9
9-3 = 6
6-3 = 3
3-3 = 0

how many times did I subtract the 3 so that nothing was left ?
4 times
so 12/3=4

so 45/0 = ??
45-0 = 45
45-0=45
45-0=45
...
how many times will I have to do this before nothing is left???
I guess I could keep this up for all eternity

so we say 45/0 is infinitely large or undefined

another way:
24/4 = 6 because 4*6 = 24
then 45/0 = x because x*0=45
but anything times zero is zero!
so x cannot be a number as we know it.
so 45/0 does not have an answer as we know it, so we call it undefined.