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About this video
A one-minute challenge of quick integer sums: check how fast you can calculate with positive and negative numbers. Then time yourself on the ten sums below.
Extra worked examples
✍️ Extra example: −7 + 12
- 112 − 7 = 5The signs differ, so subtract the smaller size from the bigger one.
- 2−7 + 12 = 5Keep the sign of the bigger size: 12 is positive. On a number line: start at −7 and move 12 to the right.
✍️ Extra example: −4 − (−9)
- 1−4 + 9Two minus signs next to each other make a plus.
- 2= 5Start at −4 and move 9 to the right.
Exercises to try
Work each one out, then click to reveal the answer.
- 1Calculate: (a) −6 + 2 (b) 3 − 8
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(a) −4 (b) −5 - 2Calculate: (a) −5 − 4 (b) −9 + 9
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(a) −9 (b) 0 - 3Calculate: (a) 7 − (−3) (b) −2 − (−6)
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(a) 10 (b) 4 - 4Calculate: (a) −8 + (−5) (b) 10 + (−13)
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(a) −13 (b) −3 - 5Calculate: (a) −15 + 20 − 4 (b) −1 − 1 − 1
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(a) 1 (b) −3
