Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 114 · 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. 1.962 − 388 =
2. 2.712 − 308 =
3. 3.958 − 499 =
4. 4.659 − 458 =
5. 5.419 − 228 =
6. 6.665 − 427 =
7. 7.906 − 259 =
8. 8.749 − 127 =
9. 9.741 − 699 =
10. 10.960 − 799 =
11. 11.766 − 478 =
12. 12.590 − 497 =
13. 13.777 − 267 =
14. 14.925 − 197 =
15. 15.868 − 297 =
16. 16.869 − 429 =
17. 17.775 − 587 =
18. 18.781 − 697 =
19. 19.425 − 199 =
20. 20.944 − 349 =
21. 21.314 − 207 =
22. 22.977 − 498 =
23. 23.746 − 399 =
24. 24.531 − 498 =
25. 25.506 − 198 =
26. 26.943 − 399 =
27. 27.972 − 477 =
28. 28.993 − 648 =
29. 29.987 − 299 =
30. 30.683 − 597 =
31. 31.631 − 399 =
32. 32.957 − 597 =
33. 33.421 − 197 =
34. 34.253 − 199 =
35. 35.903 − 499 =
36. 36.288 − 197 =
37. 37.280 − 169 =
38. 38.689 − 158 =
39. 39.334 − 298 =
40. 40.922 − 458 =

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