Chapter 5 - Number Theory and the Real Number System - 5.6 Exponents and Scientific Notation - Exercise Set 5.6 - Page 320: 108

$1.3\cdot10^{-4}$

$(2\cdot10^2)(2.6\cdot10^{-3})\div(4\cdot10^3)=\frac{(2\cdot2.6)\cdot(10^2\cdot10^{-3})}{4\cdot10^3}=\frac{5.2\cdot10^{2-3}}{4\cdot10^3}=\frac{5.2\cdot10^{-1}}{4\cdot10^3}=\frac{5.2}{4}\frac{10^{-1}}{10^3}=1.3\cdot10{-1-3}=1.3\cdot10^{-4}$