Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 570 · 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. 1.388 − 367 =
2. 2.742 − 398 =
3. 3.721 − 698 =
4. 4.469 − 418 =
5. 5.915 − 188 =
6. 6.779 − 299 =
7. 7.923 − 287 =
8. 8.482 − 297 =
9. 9.653 − 449 =
10. 10.836 − 698 =
11. 11.957 − 239 =
12. 12.671 − 627 =
13. 13.823 − 197 =
14. 14.809 − 587 =
15. 15.929 − 188 =
16. 16.831 − 367 =
17. 17.933 − 427 =
18. 18.627 − 498 =
19. 19.808 − 598 =
20. 20.974 − 597 =
21. 21.514 − 399 =
22. 22.983 − 457 =
23. 23.744 − 537 =
24. 24.685 − 258 =
25. 25.993 − 279 =
26. 26.664 − 599 =
27. 27.786 − 359 =
28. 28.303 − 197 =
29. 29.578 − 298 =
30. 30.417 − 239 =
31. 31.746 − 299 =
32. 32.652 − 257 =
33. 33.831 − 659 =
34. 34.529 − 398 =
35. 35.798 − 497 =
36. 36.994 − 499 =
37. 37.812 − 157 =
38. 38.781 − 199 =
39. 39.922 − 498 =
40. 40.982 − 148 =

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