Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 347 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.645 − 597 =
2. 2.850 − 609 =
3. 3.704 − 319 =
4. 4.530 − 498 =
5. 5.440 − 398 =
6. 6.378 − 179 =
7. 7.822 − 697 =
8. 8.896 − 197 =
9. 9.814 − 298 =
10. 10.807 − 668 =
11. 11.800 − 508 =
12. 12.751 − 197 =
13. 13.496 − 409 =
14. 14.759 − 259 =
15. 15.994 − 799 =
16. 16.846 − 799 =
17. 17.934 − 797 =
18. 18.915 − 238 =
19. 19.925 − 799 =
20. 20.950 − 499 =
21. 21.383 − 257 =
22. 22.529 − 299 =
23. 23.940 − 299 =
24. 24.925 − 798 =
25. 25.936 − 128 =
26. 26.627 − 289 =
27. 27.495 − 429 =
28. 28.940 − 597 =
29. 29.843 − 658 =
30. 30.859 − 497 =
31. 31.820 − 188 =
32. 32.588 − 377 =
33. 33.432 − 379 =
34. 34.815 − 198 =
35. 35.662 − 207 =
36. 36.900 − 498 =
37. 37.877 − 347 =
38. 38.711 − 638 =
39. 39.574 − 459 =
40. 40.666 − 298 =

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