Multi-step problems with positive and negative numbers, and checking they make sense

Answer Key - Grade 7 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   At 6 p.m., Ari's thermometer reads -3.5°F. The temperature changes by -1.25 degrees each hour for 3 hours. What is the total change, and what does the thermometer read then?

   -3.75, -7.25
2. 2.

   Bo's kite is 12 m high. Each minute its height changes by -1.5 m, for 5 minutes. What is the total change in height, and how high is the kite then?

   -7.5, 4.5
3. 3.

   Esme's robot starts at -2.5 on a number line. Each step changes its place by 0.75, for 7 steps. What is the total change, and where does the robot end?

   5.25, 2.75
4. 4.

   Jun watches a whale at -6.5 m (below the surface is negative). Each second its depth changes by -2.5 m, for 3 seconds. What is the total change, and where is it then?

   -7.5, -14

5. Read this first

   Use this

   A table of four rows. Row | As given | As a decimal: 1 | -3/4 | -0.75; 2 | 0.5 | 0.5; 3 | -1/4 | -0.25; 4 | 2 | 2.

6. 5.

   Luz logs how a pond's water level changes each day, in cm. The table shows each change two ways. What is the total change for the four days?

   1.5

7. Use this

   A table of four rows. Row | As given | As a decimal: 1 | 1/2 | 0.5; 2 | -1.25 | -1.25; 3 | 1.5 | 1.5; 4 | -3 | -3.

8. 6.

   Milo logs how the temperature changes on four days, in degrees. The table shows each change two ways. What is the total change?

   -2.25

9. Use this

   A table of four rows. Row | As given | As a decimal: 1 | 2.5 | 2.5; 2 | -1/4 | -0.25; 3 | -3/4 | -0.75; 4 | 1/4 | 0.25.

10. 7.

    Pia logs how the thickness of a pond's ice changes on four days, in cm. The table shows each change two ways. What is the total change?

    1.75
11. 8.

    Ren multiplies (-4.9) × 3.1 on a phone calculator, but the screen is smudged. Use a quick estimate. Which answer makes sense?

    • -1.519
    • -151.9
    • -15.19
    • 15.19
12. 9.

    Zee multiplies (-3.9) × (-5.2) in pencil, but the answer is smudged. Use a quick estimate. Which answer makes sense?

    • 2.028
    • 20.28
    • -20.28
    • 202.8
13. 10.

    Ari multiplies 4.2 × (-3.8) before the bell, but the answer is smudged. Use a quick estimate. Which answer makes sense?

    • -1.596
    • -15.96
    • 15.96
    • -159.6