Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 851 · 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. 1.735 − 609 =
2. 2.584 − 129 =
3. 3.755 − 499 =
4. 4.892 − 598 =
5. 5.249 − 219 =
6. 6.578 − 499 =
7. 7.322 − 157 =
8. 8.612 − 398 =
9. 9.338 − 188 =
10. 10.578 − 197 =
11. 11.422 − 198 =
12. 12.327 − 199 =
13. 13.867 − 698 =
14. 14.570 − 398 =
15. 15.889 − 797 =
16. 16.824 − 799 =
17. 17.748 − 698 =
18. 18.731 − 399 =
19. 19.737 − 699 =
20. 20.913 − 498 =
21. 21.626 − 597 =
22. 22.702 − 429 =
23. 23.693 − 639 =
24. 24.602 − 297 =
25. 25.827 − 599 =
26. 26.671 − 528 =
27. 27.521 − 498 =
28. 28.859 − 499 =
29. 29.862 − 799 =
30. 30.694 − 649 =
31. 31.627 − 169 =
32. 32.904 − 298 =
33. 33.498 − 218 =
34. 34.949 − 499 =
35. 35.708 − 587 =
36. 36.226 − 197 =
37. 37.773 − 667 =
38. 38.775 − 147 =
39. 39.734 − 658 =
40. 40.969 − 798 =

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