1. 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

2. 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