The #1 Rule in Algebra is that you can never divide by 0.

Now, why is this?

Let's start off with an example.

Let's say you have :

10 divided by 10 is 1

Let's divide by a smaller number :

10 divided by 5 is 2

Similarly :

If you haven't noticed, the smaller the divisor (the number dividing) the larger the quotient (the output is).

The smallest non-negative number is 0.

When you divide by the smallest number possible, the output will be the largest number possible.

The thing is, we don't actually know the largest number.

*Note : If you say infinity is the largest number possible, it actually isn't! Infinity is just a concept meant to represent the largest possible number.

Because we don't know the largest number, we cannot divide by 0.