UA · Unit 2 review

1. 1.

   Use a number line: start at −2 and add −6. Where do you land?

   Answer. −8

   Adding a negative moves left: −2 + (−6) = −8.

2. 2.

   Compute −6 + (12).

   Answer. 6

   −6 + (12) = 6.

3. 3.

   Rewrite 7 − (−2) as addition, then evaluate.

   Answer. 9

   Subtracting −2 is adding 2: 7 + 2 = 9.

4. 4.

   Compute −8 − (−2).

   Answer. −6

   −8 − (−2) = −6.

5. 5.

   Use a number line: start at −7 and add −6. Where do you land? Then Elena needs 4 of that amount. What is the total they need?

   Answer. −52

   Adding a negative moves left: −7 + (−6) = −13. Then multiply by 4: −52.

6. 6.

   Compute 4 + (5). Then Ava needs 2 of that amount. What is the total they need?

   Answer. 18

   4 + (5) = 9. Then multiply by 2: 18.

7. 7.

   Rewrite 2 − (−7) as addition, then evaluate. Then Sam needs 4 of that amount. What is the total they need?

   Answer. 36

   Subtracting −7 is adding 7: 2 + 7 = 9. Then multiply by 4: 36.

8. 8.

   Compute −3 − (15). Then Jonah needs 4 of that amount. What is the total they need?

   Answer. −72

   −3 − (15) = −18. Then multiply by 4: −72.

9. 9.

   Use a number line: start at −7 and add −1. Where do you land? Then Mei needs 2 of that amount. What is the total they need?

   Answer. −16

   Adding a negative moves left: −7 + (−1) = −8. Then multiply by 2: −16.

10. 10.

    Compute −2 + (6). Then Owen needs 5 of that amount. What is the total they need?

    Answer. 20

    −2 + (6) = 4. Then multiply by 5: 20.

11. 11.

    Think

    Mei tried this problem:
    Rewrite 4 − (−1) as addition, then evaluate.
    Mei wrote -5. That is not correct. What is the right answer?

    Answer. 5

    Mei’s answer -5 is off. Subtracting −1 is adding 1: 4 + 1 = 5.

12. 12.

    Think

    Theo tried this problem:
    Compute 2 − (−2).
    Theo wrote -4. That is not correct. What is the right answer?

    Answer. 4

    Theo’s answer -4 is off. 2 − (−2) = 4.

Original extra practice. Keys are computed from the items, not guessed.