In this lesson, we developed a rule for dividing powers of 10: Dividing powers of 10 is the same as subtracting the exponent of the denominator from the exponent of the numerator. To see this, take $10^5$ and divide it by $10^2$. 

We know that $10^5$ has 5 factors that are 10, and 2 of these factors can be divided by the 2 factors of 10 in $10^2$ to make 1. That leaves $5-2=3$ factors of 10, or $10^3$.

This will work for other powers of 10, too. For example $\frac{10^{56}}{10^{23}}=10^{56-23}=10^{33}$.

This rule also extends to $10^0$. If we look at $\frac{10^6}{10^0}$, using the exponent rule gives $10^{6-0}$, which is equal to $10^6$. So dividing $10^6$ by $10^0$doesn’t change its value. That means if we want the rule to work when the exponent is 0, then $10^0$ must equal 1.