Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 866 · 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. 1.356 − 197 =
2. 2.945 − 199 =
3. 3.445 − 398 =
4. 4.847 − 617 =
5. 5.574 − 299 =
6. 6.662 − 397 =
7. 7.716 − 297 =
8. 8.812 − 499 =
9. 9.743 − 679 =
10. 10.938 − 249 =
11. 11.757 − 499 =
12. 12.917 − 799 =
13. 13.935 − 577 =
14. 14.442 − 258 =
15. 15.650 − 469 =
16. 16.569 − 199 =
17. 17.702 − 287 =
18. 18.311 − 199 =
19. 19.665 − 598 =
20. 20.659 − 598 =
21. 21.979 − 599 =
22. 22.814 − 298 =
23. 23.918 − 799 =
24. 24.916 − 299 =
25. 25.659 − 308 =
26. 26.620 − 499 =
27. 27.352 − 297 =
28. 28.805 − 498 =
29. 29.925 − 199 =
30. 30.698 − 279 =
31. 31.779 − 599 =
32. 32.871 − 297 =
33. 33.818 − 797 =
34. 34.853 − 509 =
35. 35.833 − 499 =
36. 36.650 − 499 =
37. 37.718 − 597 =
38. 38.353 − 318 =
39. 39.592 − 167 =
40. 40.560 − 538 =

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