This download consists of the 5 PowerPoints used to make the videos for each section of chapter 15 listed below. Addition & Subtraction of Rational Numbers15.1 Introduction…5 slides15.2 Strategies for Adding Rational Numbers…24 slides15.3 Strategies for adding Mixed Fractions…15 slides15.4 Strategies for Subtracting Rational Numbers…23 slides15.5 Strategies for Subtracting Mixed Fractions…25 slides