Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 560 · 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. 1.781 − 297 =
2. 2.471 − 167 =
3. 3.971 − 797 =
4. 4.852 − 648 =
5. 5.855 − 477 =
6. 6.697 − 598 =
7. 7.730 − 599 =
8. 8.827 − 398 =
9. 9.590 − 297 =
10. 10.664 − 477 =
11. 11.475 − 407 =
12. 12.619 − 597 =
13. 13.309 − 207 =
14. 14.781 − 307 =
15. 15.667 − 197 =
16. 16.961 − 397 =
17. 17.938 − 677 =
18. 18.357 − 117 =
19. 19.407 − 238 =
20. 20.698 − 297 =
21. 21.593 − 197 =
22. 22.741 − 478 =
23. 23.878 − 499 =
24. 24.562 − 197 =
25. 25.884 − 259 =
26. 26.481 − 317 =
27. 27.281 − 199 =
28. 28.782 − 598 =
29. 29.944 − 599 =
30. 30.807 − 499 =
31. 31.937 − 628 =
32. 32.792 − 699 =
33. 33.903 − 497 =
34. 34.869 − 147 =
35. 35.863 − 797 =
36. 36.967 − 359 =
37. 37.656 − 167 =
38. 38.720 − 599 =
39. 39.968 − 567 =
40. 40.983 − 499 =

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