Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 684 · 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. 1.763 − 698 =
2. 2.848 − 397 =
3. 3.700 − 138 =
4. 4.982 − 599 =
5. 5.702 − 678 =
6. 6.819 − 798 =
7. 7.868 − 799 =
8. 8.997 − 297 =
9. 9.684 − 197 =
10. 10.277 − 138 =
11. 11.572 − 488 =
12. 12.731 − 399 =
13. 13.367 − 287 =
14. 14.326 − 198 =
15. 15.481 − 119 =
16. 16.712 − 598 =
17. 17.615 − 478 =
18. 18.876 − 699 =
19. 19.658 − 297 =
20. 20.897 − 497 =
21. 21.613 − 267 =
22. 22.818 − 699 =
23. 23.727 − 598 =
24. 24.847 − 458 =
25. 25.824 − 248 =
26. 26.982 − 549 =
27. 27.860 − 797 =
28. 28.764 − 198 =
29. 29.565 − 209 =
30. 30.687 − 119 =
31. 31.539 − 139 =
32. 32.805 − 269 =
33. 33.622 − 198 =
34. 34.792 − 267 =
35. 35.617 − 197 =
36. 36.736 − 498 =
37. 37.371 − 199 =
38. 38.871 − 597 =
39. 39.918 − 118 =
40. 40.534 − 497 =

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