Chapter 2 - Section 2.5 - Powers of 10 - Exercises - Page 122: 22

$10^0=1$

$\frac{10^0\times10^{-3}}{10^{-6}\times10^3}\longrightarrow$ to multiply powers of 10, add the exponents $=\frac{10^{0+(-3)}}{10^{-6+3}}$ $=\frac{10^{-3}}{10^{-3}}\longrightarrow$ to divide powers of 10, subtract the exponents $=10^{-3-(-3)}$ $=10^{-3+3}$ $=10^0=1$