Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 600 · 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. 1.896 − 799 =
2. 2.739 − 438 =
3. 3.757 − 587 =
4. 4.923 − 298 =
5. 5.612 − 299 =
6. 6.507 − 429 =
7. 7.982 − 697 =
8. 8.776 − 438 =
9. 9.483 − 197 =
10. 10.902 − 799 =
11. 11.689 − 498 =
12. 12.422 − 379 =
13. 13.700 − 638 =
14. 14.847 − 598 =
15. 15.867 − 697 =
16. 16.922 − 559 =
17. 17.919 − 299 =
18. 18.571 − 349 =
19. 19.630 − 397 =
20. 20.924 − 298 =
21. 21.762 − 399 =
22. 22.966 − 259 =
23. 23.995 − 408 =
24. 24.983 − 397 =
25. 25.793 − 609 =
26. 26.301 − 198 =
27. 27.735 − 198 =
28. 28.833 − 299 =
29. 29.891 − 697 =
30. 30.670 − 398 =
31. 31.943 − 799 =
32. 32.670 − 567 =
33. 33.684 − 469 =
34. 34.776 − 199 =
35. 35.844 − 628 =
36. 36.624 − 609 =
37. 37.895 − 499 =
38. 38.675 − 569 =
39. 39.804 − 598 =
40. 40.353 − 159 =

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