Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 98 · 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. 1.415 − 318 =
2. 2.689 − 599 =
3. 3.964 − 799 =
4. 4.409 − 347 =
5. 5.763 − 547 =
6. 6.370 − 299 =
7. 7.668 − 118 =
8. 8.678 − 299 =
9. 9.380 − 318 =
10. 10.673 − 299 =
11. 11.850 − 798 =
12. 12.796 − 599 =
13. 13.798 − 697 =
14. 14.982 − 498 =
15. 15.479 − 299 =
16. 16.878 − 118 =
17. 17.817 − 407 =
18. 18.664 − 498 =
19. 19.828 − 509 =
20. 20.845 − 507 =
21. 21.287 − 217 =
22. 22.717 − 247 =
23. 23.619 − 547 =
24. 24.801 − 599 =
25. 25.898 − 498 =
26. 26.644 − 599 =
27. 27.934 − 798 =
28. 28.564 − 397 =
29. 29.966 − 659 =
30. 30.914 − 407 =
31. 31.760 − 497 =
32. 32.958 − 699 =
33. 33.882 − 208 =
34. 34.348 − 198 =
35. 35.767 − 687 =
36. 36.608 − 299 =
37. 37.930 − 457 =
38. 38.946 − 499 =
39. 39.926 − 598 =
40. 40.891 − 798 =

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