Why x*0 = x

[Excited Penguin]

That doesn't explain it, the correct explanation is now create piles of zero books, how many piles would you need?

That's not correct. The number of books in the pile is the outcome of the division, not the number we're dividing by. As in 5 piles of 2 books each is 10/5=0. The number of piles is what we're dividing by, so the question of 10/0 is the question of dividing 10 books into 0 piles. Physically impossible.

You don't divide them at all so it should be zero.

I'm just trying to apply common sense, I already know I'm wrong.