Evaluate variable expressions involving rational numbers
Evaluating expressions with rational numbers (fractions and decimals) follows the same rules as with integers. Substitute the given value for the variable and use the order of operations to solve.
Do this: Read the concept below, then try the quiz or activity.
Lesson 2 of 192
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Concept
Example 1: With Decimals Evaluate 2.5x + 1.2 when x = 3.
1. Substitute: 2.5(3) + 1.2 2. Simplify: 7.5 + 1.2 3. Solve: 8.7
Example 2: With Fractions Evaluate (1/2)y - 1/4 when y = 3/2.
1. Substitute: (1/2)(3/2) - 1/4 2. Simplify: 3/4 - 1/4 3. Solve: 2/4 = 1/2
Try it
Practice: Evaluate variable expressions involving rational numbers.