Numbers and operations · Ages 12–13
Adding directed numbers worksheet
Part of: Directed numbers
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Adding directed numbers worksheet
Numbers and operations · Ages 12–13
Numsprite
numsprite.com
Name:Date:Score:／48
Write each answer in the space. For word problems, show your working and write a sentence answer.
Part A: Working out and filling in (2 marks each)
1.(+20) + (+7) =
Answer:
2.(−9) + 2 =
Answer:
3.50 + (−28) =
Answer:
4.(−3) + 8 =
Answer:
5.34 + (−24) =
Answer:
6.(−31) + 34 =
Answer:
7.(−8) + 5 + (−10): the negatives make − together; adding 5 gives .
Fill in each blank
Answer:
8.(−3) + 44 =
Answer:
9.(−13) + 12 + (−10): the negatives make − together; adding 12 gives .
Fill in each blank
Answer:
10.(−8.7) + (−6.1) =
Answer:
11.(−56) + 23 =
Answer in simplest form
Answer:
12.(+2.5) + (−7.7) =
Answer:
Part B: Word problems (4 marks each)
13.On a hill it is −9°C at dawn. Up 11°C, it is °C. Down 3°C again by dusk, it is °C.
Fill in each blank
Working:
Answer:
14.The ground floor G is 0 and B2 is −2. A lift goes up 2 floors from B2, then down 3. Which floor does it stop at? Give a number, basements negative.
Working:
Answer:
15.It was −9°C before dawn and it rose 2°C by noon. What was the temperature at noon?
Working:
Answer:
16.East is positive and the start is 0. A cat walks −90, +105, −40 m: m in all, ending at m.
Fill in each blank
Working:
Answer:
17.A team's goal differences in four matches are +1, −2, +6, −3. What is its goal difference over the four?
Working:
Answer:
18.A counter starts on square 0, moves back 5, back 4, then forward 11. With forward positive, where is it now?
Working:
Answer:
Show the answers and working
Adding directed numbers worksheet: Answers and working
Part A: Working out and filling in
1. 27
Same signs: add the sizes and keep the sign. 20 + 7, so the answer is 27.
2. −7
From −9, move 2 right to reach −7. Adding a positive moves right, not left; with different signs, subtract the sizes rather than add them, and take the sign of the one further from 0.
3. 22
Adding a negative moves left: 50 − 28 = 22. The sign is that of the number further from 0.
4. 5
From −3, move 8 right to reach 5. Adding a positive moves right, not left; with different signs, subtract the sizes rather than add them, and take the sign of the one further from 0.
5. 10
Adding a negative moves left: 34 − 24 = 10. The sign is that of the number further from 0.
6. 3
With different signs, subtract the sizes; don't add them. 34 and 31 subtracted, with the sign of the one further from 0: 3.
7. 18, −13
Gather the negatives first: −8 and −10 make −18. Then 5 + (−18) = −13.
8. 41
With different signs, subtract the sizes; don't add them. 44 and 3 subtracted, with the sign of the one further from 0: 41.
9. 23, −11
Gather the negatives first: −13 and −10 make −23. Then 12 + (−23) = −11.
10. −14.8
Decimals work the same way: same signs, add the sizes and keep the sign; different signs, subtract them and take the sign of the one further from 0. The answer is −14.8.
11. −16
Common denominator first, then subtract as the signs differ, keeping the sign of the one further from 0: −16, in lowest terms.
12. −5.2
Decimals work the same way: same signs, add the sizes and keep the sign; different signs, subtract them and take the sign of the one further from 0. The answer is −5.2.
Part B: Word problems
Marking: 2 for the working, 1 for the answer, 1 for the sentence.
13. 2, −1
(−9) + 11 = 2, and 2 + (−3) = −1.
14. −3
(−2) + 2 + (−3) = −3.
15. −7°C
(−9) + 2 = −7. It takes 9°C just to reach 0°C; if it rises less, it is still below zero.
16. 235, −25
Distance ignores direction, so add them all: 235 m. Position counts direction: (−90) + 105 + (−40) = −25.
17. 2 goals
The positives add to 1 + 6 and the negatives to −(2 + 3); together they make 2.
18. 2
Moving back is negative, and the two moves back add: (−5) + (−4) = −(5 + 4); adding 11 gives 2.
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