Work through the levels in order. Type your answer and press Check — open the worked solution if you get stuck. Answers like -6, 3/4 or 0.25 are typed exactly as shown.
Level 1 · Warm-up
1 Work out −6 + 4. (as an integer)
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Four hops right from −6 give −5, −4, −3, −2. So −6 + 4 = −2.
2 Work out 3 + (−8). (as an integer)
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3 + (−8) = 3 − 8. Eight hops left from 3 lands on −5.
3 Work out −5 + (−2). (as an integer)
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−5 + (−2) = −5 − 2 = −7. Both parts push you further from zero.
Level 2 · Core
4 Work out 7 − (−4). (as an integer)
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7 − (−4) = 7 + 4 = 11. Subtracting a negative moves you to the right.
5 Work out −3 − (−9). (as an integer)
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−3 − (−9) = −3 + 9. Nine hops right from −3 lands on 6.
6 Work out −12 − 5. (as an integer)
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Five hops left from −12 gives −17.
Level 3 · Challenge
7 Work out −8 − (−3) + 5. (as an integer)
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−8 − (−3) + 5 = −8 + 3 + 5 = −5 + 5 = 0.
8 At 6 pm the temperature is −2 °C. Overnight it falls 7 degrees, then by noon it rises 4 degrees. What is the temperature at noon? (as an integer number of degrees)
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−2 − 7 = −9, then −9 + 4 = −5 °C.
9 How many degrees warmer is 5 °C than −9 °C? (as an integer number of degrees)
Show worked solution
5 − (−9) = 5 + 9 = 14 degrees. On the line it is 9 hops up to zero and 5 more after that.