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. A ⭐ Bonus Challenge at the end is extra credit — skip it if the rest was hard work.
Level 1 · Warm-up
1 Which number is 3 less than 1?
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1 → 0 → −1 → −2.
2 Put these temperatures in order, coldest first: 4 °C, −6 °C, −1 °C.
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Left to right: −6, −1, 4.
3 The temperature is 6 °C and falls by 10 degrees. What is the new temperature, in °C?
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6 − 10: six hops to zero, four more to −4.
Level 2 · Core
4 The diagram shows heights above and below sea level. How many metres is the submarine below the fish?
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The fish is 15 below, the submarine 40 below. Same side of zero: 40 − 15 = 25 m.
5 For −9 and 7, give the difference between them and the number exactly halfway between them.
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Difference: 9 + 7 = 16. Half is 8, and −9 + 8 = −1.
6 Anya's bank account is at −$13 (she owes $13). She deposits $20. What is the balance now, in dollars?
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−13 + 20: 13 brings it to zero, 7 more makes $7.
Level 3 · Challenge
7 Three statements are made about −9 and −8.1 −9 is less than −8.
2 The difference between −9 and −8 is 17.
3 −9 + 17 = 8.
Which statements are correct?
2 The difference between −9 and −8 is 17.
3 −9 + 17 = 8.
Which statements are correct?
Show worked solution
−9 is left of −8, so it is less (1 ✓). They are one apart, not 17 (2 ✗). −9 + 17: nine hops to zero, eight more → 8 (3 ✓). 1 and 3.
8 A number line runs from −12 at one end to 18 at the other. Give the distance between the ends and the number in the exact middle.
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Distance: 12 + 18 = 30. Half is 15; −12 + 15 = 3.
9 During the day the temperature rose 14 degrees, then fell 9 degrees, and finished at −2 °C. What was the temperature at the start, in °C?
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Undo the fall: −2 + 9 = 7. Undo the rise: 7 − 14 = −7.