Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 199 · 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. 1.934 − 597 =
2. 2.333 − 178 =
3. 3.688 − 118 =
4. 4.448 − 298 =
5. 5.540 − 397 =
6. 6.763 − 699 =
7. 7.955 − 688 =
8. 8.744 − 398 =
9. 9.957 − 617 =
10. 10.636 − 498 =
11. 11.822 − 799 =
12. 12.819 − 699 =
13. 13.283 − 199 =
14. 14.489 − 138 =
15. 15.651 − 529 =
16. 16.772 − 229 =
17. 17.607 − 447 =
18. 18.579 − 239 =
19. 19.758 − 198 =
20. 20.625 − 497 =
21. 21.729 − 269 =
22. 22.842 − 297 =
23. 23.896 − 177 =
24. 24.529 − 299 =
25. 25.868 − 798 =
26. 26.778 − 617 =
27. 27.817 − 798 =
28. 28.439 − 199 =
29. 29.806 − 679 =
30. 30.248 − 197 =
31. 31.834 − 159 =
32. 32.823 − 599 =
33. 33.582 − 547 =
34. 34.447 − 318 =
35. 35.449 − 297 =
36. 36.450 − 117 =
37. 37.278 − 198 =
38. 38.962 − 537 =
39. 39.707 − 448 =
40. 40.806 − 499 =

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