Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 287 · 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. 1.899 − 397 =
2. 2.627 − 598 =
3. 3.609 − 488 =
4. 4.472 − 298 =
5. 5.935 − 577 =
6. 6.468 − 399 =
7. 7.576 − 497 =
8. 8.734 − 598 =
9. 9.789 − 698 =
10. 10.801 − 697 =
11. 11.828 − 299 =
12. 12.959 − 699 =
13. 13.999 − 448 =
14. 14.797 − 127 =
15. 15.638 − 299 =
16. 16.646 − 197 =
17. 17.928 − 497 =
18. 18.445 − 199 =
19. 19.387 − 349 =
20. 20.826 − 398 =
21. 21.636 − 497 =
22. 22.699 − 169 =
23. 23.925 − 498 =
24. 24.504 − 168 =
25. 25.625 − 267 =
26. 26.659 − 299 =
27. 27.952 − 668 =
28. 28.251 − 177 =
29. 29.736 − 277 =
30. 30.417 − 398 =
31. 31.896 − 399 =
32. 32.931 − 267 =
33. 33.659 − 599 =
34. 34.891 − 539 =
35. 35.827 − 449 =
36. 36.410 − 197 =
37. 37.747 − 398 =
38. 38.359 − 298 =
39. 39.853 − 537 =
40. 40.948 − 269 =

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