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 strategy fits 6 995 + 2 340 best?
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6 995 is 5 short of 7 000. Compensate: use 7 000, then take 5 off — 7 000 + 2 340 = 9 340, then − 5 = 9 335.
2 Work out 5 997 + 3 480 by compensating. Give the friendly number you used and the answer.
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Use 6 000: 6 000 + 3 480 = 9 480, then take the 3 back off: 9 477.
3 Work out 8 000 − 6 540.
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6 540 → 7 000 is 460; 7 000 → 8 000 is 1 000. 1 460.
Level 2 · Core
4 Work out 4 356 + 2 830.
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6 000 + 1 100 + 80 + 6 = 7 186.
5 Work out 10 000 − 4 215 by bridging. Give each jump and the answer.
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4 215 → 5 000 is 785. 5 000 → 10 000 is 5 000. Total 5 785.
6 Work out 7 003 − 2 996.
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7 000 − 3 000 = 4 000. The 7 003 was 3 more (add 3); the 2 996 was 4 less than 3 000, so you took 4 too many (add 4): 4 000 + 3 + 4 = 4 007.
Level 3 · Challenge
7 Zara works out 12 000 − 3 995 − 4 260 three ways.1 12 000 − 4 000 + 5 = 8 005, then 8 005 − 4 260 = 3 745.
2 3 995 + 4 260 = 8 255, then 12 000 − 8 255 = 3 745.
3 12 000 − 4 000 − 5 = 7 995, then 7 995 − 4 260 = 3 735.
Which of her workings are correct?
2 3 995 + 4 260 = 8 255, then 12 000 − 8 255 = 3 745.
3 12 000 − 4 000 − 5 = 7 995, then 7 995 − 4 260 = 3 735.
Which of her workings are correct?
Show worked solution
Working 1 compensates correctly (took 5 too many, gives 5 back). Working 2 adds the sales first — also right. Working 3 subtracts the 5 as well, so it takes away 4 005 instead of 3 995 — wrong. 1 and 2.
8 A rope is 9 000 cm long. Ari cuts off 2 998 cm, then 1 750 cm. Give the length after the first cut and after the second.
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9 000 − 2 998 = 6 002 (take 3 000, give 2 back). 6 002 − 1 750 = 4 252.
9 Ben adds 2 995 to a number, then subtracts 4 000, and gets 6 750. What number did he start with?
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Undo the − 4 000: 6 750 + 4 000 = 10 750. Undo the + 2 995: 10 750 − 2 995 = 10 750 − 3 000 + 5 = 7 755.