Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 489 · 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. 1.879 − 297 =
2. 2.642 − 597 =
3. 3.711 − 598 =
4. 4.875 − 428 =
5. 5.894 − 499 =
6. 6.900 − 798 =
7. 7.392 − 267 =
8. 8.710 − 149 =
9. 9.573 − 398 =
10. 10.424 − 328 =
11. 11.626 − 498 =
12. 12.621 − 497 =
13. 13.704 − 179 =
14. 14.510 − 438 =
15. 15.517 − 199 =
16. 16.406 − 299 =
17. 17.960 − 797 =
18. 18.648 − 299 =
19. 19.654 − 398 =
20. 20.807 − 548 =
21. 21.674 − 597 =
22. 22.457 − 169 =
23. 23.963 − 619 =
24. 24.535 − 199 =
25. 25.665 − 638 =
26. 26.827 − 598 =
27. 27.936 − 799 =
28. 28.652 − 597 =
29. 29.216 − 119 =
30. 30.437 − 399 =
31. 31.967 − 699 =
32. 32.822 − 297 =
33. 33.868 − 618 =
34. 34.341 − 317 =
35. 35.637 − 398 =
36. 36.442 − 398 =
37. 37.775 − 697 =
38. 38.902 − 799 =
39. 39.537 − 199 =
40. 40.823 − 257 =

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