Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 48 · 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. 1.834 − 399 =
2. 2.412 − 259 =
3. 3.807 − 298 =
4. 4.724 − 557 =
5. 5.689 − 648 =
6. 6.720 − 399 =
7. 7.605 − 499 =
8. 8.822 − 157 =
9. 9.543 − 298 =
10. 10.858 − 117 =
11. 11.998 − 697 =
12. 12.716 − 597 =
13. 13.515 − 199 =
14. 14.574 − 198 =
15. 15.548 − 338 =
16. 16.652 − 409 =
17. 17.602 − 497 =
18. 18.516 − 298 =
19. 19.470 − 278 =
20. 20.439 − 147 =
21. 21.444 − 148 =
22. 22.801 − 698 =
23. 23.632 − 618 =
24. 24.850 − 497 =
25. 25.853 − 548 =
26. 26.731 − 338 =
27. 27.888 − 197 =
28. 28.328 − 289 =
29. 29.685 − 397 =
30. 30.940 − 627 =
31. 31.330 − 258 =
32. 32.962 − 697 =
33. 33.953 − 597 =
34. 34.881 − 797 =
35. 35.957 − 598 =
36. 36.510 − 298 =
37. 37.433 − 177 =
38. 38.602 − 398 =
39. 39.611 − 188 =
40. 40.962 − 497 =

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