Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 23 · 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. 1.914 − 297 =
2. 2.357 − 199 =
3. 3.608 − 197 =
4. 4.444 − 308 =
5. 5.811 − 599 =
6. 6.619 − 498 =
7. 7.959 − 227 =
8. 8.603 − 238 =
9. 9.213 − 197 =
10. 10.235 − 217 =
11. 11.662 − 499 =
12. 12.362 − 228 =
13. 13.428 − 397 =
14. 14.641 − 328 =
15. 15.383 − 297 =
16. 16.941 − 299 =
17. 17.911 − 698 =
18. 18.983 − 497 =
19. 19.967 − 199 =
20. 20.932 − 798 =
21. 21.668 − 297 =
22. 22.941 − 799 =
23. 23.448 − 169 =
24. 24.526 − 399 =
25. 25.832 − 797 =
26. 26.694 − 427 =
27. 27.963 − 468 =
28. 28.502 − 308 =
29. 29.602 − 197 =
30. 30.431 − 298 =
31. 31.722 − 597 =
32. 32.418 − 199 =
33. 33.294 − 148 =
34. 34.585 − 499 =
35. 35.795 − 299 =
36. 36.229 − 199 =
37. 37.775 − 697 =
38. 38.553 − 497 =
39. 39.767 − 697 =
40. 40.753 − 207 =

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