Adding and Subtracting Rational Numbers COURSE 3 LESSON 4-4 Adding and Subtracting Rational Numbers 1 3 3 4 A recipe calls for cup white flour and cup wheat flour. How many total cups of flour are used? 1 3 1 • 4 3 • 4 + 4 = 3 • 3 4 • 3 Write equivalent fractions with the same denominator. 4 12 = + 9 Simplify. = 13 12 Add the numerators. You need , or 1 , cups of flour. 13 12 1 4-4

Adding and Subtracting Rational Numbers COURSE 3 LESSON 4-4 Adding and Subtracting Rational Numbers Find – . 9 10 3 4 The LCM of 10 and 4 is 20, so the LCD of and is 20. 9 10 3 4 9 10 Write equivalent fractions using the LCD. 3 4 – = 18 20 15 Subtract the numerators. 18 – 15 20 3 = 4-4