Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 77 · 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. 1.902 − 597 =
2. 2.803 − 599 =
3. 3.597 − 547 =
4. 4.493 − 257 =
5. 5.951 − 499 =
6. 6.530 − 499 =
7. 7.725 − 599 =
8. 8.910 − 347 =
9. 9.728 − 249 =
10. 10.640 − 207 =
11. 11.738 − 509 =
12. 12.955 − 598 =
13. 13.999 − 499 =
14. 14.601 − 497 =
15. 15.638 − 337 =
16. 16.986 − 189 =
17. 17.816 − 398 =
18. 18.812 − 328 =
19. 19.748 − 598 =
20. 20.827 − 618 =
21. 21.575 − 288 =
22. 22.427 − 168 =
23. 23.478 − 337 =
24. 24.536 − 267 =
25. 25.912 − 799 =
26. 26.802 − 259 =
27. 27.767 − 199 =
28. 28.632 − 298 =
29. 29.442 − 377 =
30. 30.679 − 539 =
31. 31.846 − 697 =
32. 32.929 − 659 =
33. 33.720 − 197 =
34. 34.412 − 299 =
35. 35.706 − 497 =
36. 36.839 − 639 =
37. 37.735 − 479 =
38. 38.798 − 167 =
39. 39.844 − 798 =
40. 40.727 − 398 =

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