Math for Computer Science
8 | Variable expressions
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Examples
Practice Problems
Introduction
How are variable expressions evaluated?
- To evaluate a variable expression, we first substitute a value for the variable, then apply the order of operations.
- Since we can substitute any value for a variable, variable expressions can be used to predict an outcome for a given condition.
Examples
Evaluating variable expressions (one-step)
Q: Evaluate for z = 5:
z + 9
A: First, we substitute for z. Then, we add:
z + 9 = 5 + 9 = 14
Evaluating variable expressions (two-step)
Q: Evaluate for c = 3:
4 × c − 5
A: First, we substitute for c. Then, we apply the order of operations:
4 × c − 5 = 4 × 3 − 5 = 12 − 5 = 7
Practice | Variable Expressions
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