Practice
Name
5-6
Evaluating Expressions with
Decimals
Evaluate each expression by using substitution.
1. n 3 8.62; n 5 8
4. 7s 2 4; s 5 11.7
8 3 8.62 5 68.96
7 3 11.7 2 4 5 77.9
2. x 4 3.2; x 5 28.8
5. 2.94 1 h 4 4; h 5 21.6
28.8 4 3.2 5 9 2.94 1 21.6 4 4 5 8.34
6. 12.5 2 g2; g 5 2.5
3. 5r 1 (r 4 3); r 5 5.1
5 3 5.1 1 (5.1
4 3) 5 27.2 12.5 2 2.52 5 6.25
For 7 through 9, evaluate each expression for x 5 1.2, x 5 6, and x 5 9.6.
7. x 4 8
8. 3x 1 2.7
9. 4x 1 1.4x
0.15; 0.75; 1.2
6.3; 20.7; 31.5
6.48; 32.4;
51.84
10. The table shows how much a frozen yogurt shop
charges for its yogurt. Write an expression to show
how much it costs to buy a small yogurt with no
toppings and a large yogurt with x toppings. Then
solve for buying a small yogurt with no toppings
and a large yogurt with 3 toppings.
7.5 1 0.35x; $8.55
Size of
cup
Cost of Cost per
cup
topping
Small
$2.85
$0.25
Medium
$3.75
$0.30
Large
$4.65
$0.35
11. What is the value of the expression 7.2 1 10.8 4 p for p 5 2.4?
A 7.5
B 9
C 11.7
D 12.5
12. Writing to Explain Explain in words how you would evaluate the expression
5.1 1 q 4 3.4 for q 5 28.9.
Sample answer: Replace q with 28.9. Divide 28.9
by 3.4 and then add 5.1 to the quotient.
P 5•6
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