Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 567 · 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. 1.931 − 298 =
2. 2.942 − 197 =
3. 3.831 − 297 =
4. 4.909 − 178 =
5. 5.998 − 299 =
6. 6.651 − 529 =
7. 7.927 − 399 =
8. 8.635 − 499 =
9. 9.796 − 567 =
10. 10.604 − 388 =
11. 11.896 − 699 =
12. 12.845 − 298 =
13. 13.279 − 199 =
14. 14.471 − 239 =
15. 15.445 − 299 =
16. 16.794 − 199 =
17. 17.612 − 498 =
18. 18.713 − 598 =
19. 19.523 − 297 =
20. 20.875 − 799 =
21. 21.570 − 497 =
22. 22.644 − 619 =
23. 23.709 − 669 =
24. 24.831 − 399 =
25. 25.774 − 399 =
26. 26.255 − 239 =
27. 27.787 − 597 =
28. 28.817 − 698 =
29. 29.654 − 347 =
30. 30.481 − 397 =
31. 31.992 − 797 =
32. 32.705 − 267 =
33. 33.695 − 597 =
34. 34.355 − 188 =
35. 35.588 − 399 =
36. 36.875 − 579 =
37. 37.833 − 697 =
38. 38.997 − 697 =
39. 39.470 − 138 =
40. 40.987 − 599 =

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