Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 394 · 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. 1.853 − 599 =
2. 2.641 − 598 =
3. 3.744 − 699 =
4. 4.954 − 199 =
5. 5.484 − 157 =
6. 6.537 − 118 =
7. 7.987 − 239 =
8. 8.667 − 478 =
9. 9.342 − 199 =
10. 10.715 − 459 =
11. 11.802 − 597 =
12. 12.536 − 399 =
13. 13.842 − 557 =
14. 14.315 − 188 =
15. 15.555 − 218 =
16. 16.650 − 299 =
17. 17.560 − 307 =
18. 18.747 − 398 =
19. 19.814 − 569 =
20. 20.362 − 149 =
21. 21.795 − 697 =
22. 22.965 − 228 =
23. 23.656 − 208 =
24. 24.875 − 358 =
25. 25.627 − 579 =
26. 26.472 − 178 =
27. 27.499 − 397 =
28. 28.674 − 598 =
29. 29.916 − 309 =
30. 30.484 − 447 =
31. 31.771 − 699 =
32. 32.481 − 197 =
33. 33.557 − 497 =
34. 34.796 − 337 =
35. 35.724 − 699 =
36. 36.525 − 197 =
37. 37.942 − 299 =
38. 38.980 − 797 =
39. 39.723 − 649 =
40. 40.578 − 197 =

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