Why is anything to the power 0 equal 1?

This is often overlooked as no-one gives a reason to why this is and is often stated as a fact. We start off with the basic indice law of x^y * x^z = x^y+z.
For example, Likewise with division, you can have z = -w and therefore you take away
7³ * 7² = (7 * 7 * 7) * (7* 7) = 7 * 7 * 7 * 7 * 7 * 7 * 7 = 7⁷ 
Likewise with division, you can have z = -w and therefore you take away the powers. The number 0 is made through taking away two numbers that are the same, e.g. 5 - 5 or -11 + 11. This means we have 70 = 7^w * 7^-w = 7^w / 7^w = 1