Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 558 · 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. 1.948 − 298 =
2. 2.744 − 469 =
3. 3.824 − 498 =
4. 4.436 − 299 =
5. 5.881 − 227 =
6. 6.494 − 297 =
7. 7.907 − 527 =
8. 8.582 − 157 =
9. 9.750 − 669 =
10. 10.865 − 697 =
11. 11.641 − 618 =
12. 12.725 − 317 =
13. 13.870 − 308 =
14. 14.484 − 398 =
15. 15.623 − 559 =
16. 16.877 − 228 =
17. 17.860 − 398 =
18. 18.975 − 798 =
19. 19.659 − 639 =
20. 20.797 − 349 =
21. 21.825 − 639 =
22. 22.840 − 347 =
23. 23.347 − 297 =
24. 24.540 − 187 =
25. 25.908 − 169 =
26. 26.964 − 247 =
27. 27.593 − 298 =
28. 28.852 − 697 =
29. 29.990 − 199 =
30. 30.840 − 697 =
31. 31.788 − 659 =
32. 32.554 − 298 =
33. 33.352 − 257 =
34. 34.701 − 577 =
35. 35.867 − 198 =
36. 36.999 − 598 =
37. 37.237 − 197 =
38. 38.754 − 698 =
39. 39.626 − 337 =
40. 40.704 − 407 =

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