The most infamous question of all

$${\frac{{\mathtt{0}}}{{\mathtt{0}}}} = {\mathtt{C}}$$

$${\mathtt{0}} = {\mathtt{0}}{\mathtt{\,\times\,}}{\mathtt{C}}$$

$${\mathtt{0}} = {\mathtt{0}}$$

Therefore C can be any number. It is "indeterminate". I didn't make this up its from a book called "50 Mathematical Ideas You Really Need to Know" by Tony Crilly. 

Technically anything divided by 0 is endefined, but 0/0 would also technically be 1