Subtracting Signed Numbers

Which expression is equivalent to 18 - 20?

• 18 + (-20)

• 18 – (-20)

• -18 + 20

• -18 – 20

Which of the following expressions is not equivalent (not equal) to the other three? (Which would NOT give the same answer as the other three?)

• 10 + 12

• 10 – (-12)

• -10 - 12

• 12 + 10

Which situation involves opposite quantities combining to make 0?

• A bank account has a balance of $112.75, and the account owner deposits $112.75 into the account.

• A student walk 11 blocks east to school and then walks 11 blocks west back home.

• A teenager earns $16.50 filing papers at a local business and then earns $16.50 selling baked goods.

• A thermometer reads 5˚ at the beginning of the day and then increases 5˚C during the day.

Jerry borrowed $32.50 from his father. He paid back $15.25 of the money. Which represents Jerry’s debt to his father now?

• -$47.75

• -$17.25

• $17.25

• $47.75

The terms in a pattern are given in the table. What is the value of the 5^th term?

• -7

• 7

• -5

• 5

The record for the lowest temperature in Kentucky is -37°F. The record for the lowest temperature in the United States is 43°F cooler than Kentucky’s record. What is the record for the LOWEST temperature in the United States?

• -80˚F

• -70˚F

• -16˚F

• -6˚F

What is the value of 8⅗ + (-4⅖) - 11⅕?

• -7 1/20

• -7

• -5 4/5

• -1/5

An airplane takes off and then climbs 2500 feet. After 20 minutes, the airplane descends 150 feet. What integer represents the airplane's current height?

Determine the value of the unknown:

8 - x = -5

Daredevil Danny was cliff jumping. He jumped off a cliff that was 14.2 meters above the surface of the water. At the end of his jump, Danny was 2.3 meters below the surface of the water.

The following equation describes this situation:

14.2 + (−16.5) = −2.3

What does -16.5 tell us?

• The distance from the cliff to the surface of the water is 16.5 meters.

• Danny reached a depth of 16.5 meters at the end of his jump.

• None of the above.