Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 310 · 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. 1.777 − 669 =
2. 2.791 − 119 =
3. 3.392 − 139 =
4. 4.633 − 448 =
5. 5.864 − 399 =
6. 6.622 − 499 =
7. 7.940 − 698 =
8. 8.697 − 437 =
9. 9.843 − 798 =
10. 10.826 − 399 =
11. 11.513 − 258 =
12. 12.365 − 198 =
13. 13.856 − 458 =
14. 14.928 − 699 =
15. 15.802 − 599 =
16. 16.659 − 588 =
17. 17.747 − 499 =
18. 18.954 − 438 =
19. 19.796 − 599 =
20. 20.653 − 598 =
21. 21.527 − 497 =
22. 22.502 − 298 =
23. 23.560 − 399 =
24. 24.938 − 138 =
25. 25.324 − 199 =
26. 26.514 − 309 =
27. 27.775 − 279 =
28. 28.672 − 657 =
29. 29.749 − 699 =
30. 30.520 − 197 =
31. 31.662 − 487 =
32. 32.999 − 498 =
33. 33.740 − 598 =
34. 34.972 − 799 =
35. 35.826 − 599 =
36. 36.952 − 159 =
37. 37.512 − 249 =
38. 38.605 − 308 =
39. 39.924 − 397 =
40. 40.567 − 199 =

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