Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 311 · 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. 1.810 − 259 =
2. 2.550 − 188 =
3. 3.970 − 797 =
4. 4.445 − 237 =
5. 5.811 − 599 =
6. 6.684 − 397 =
7. 7.879 − 627 =
8. 8.804 − 609 =
9. 9.572 − 397 =
10. 10.924 − 799 =
11. 11.858 − 799 =
12. 12.657 − 567 =
13. 13.981 − 797 =
14. 14.884 − 398 =
15. 15.494 − 229 =
16. 16.889 − 227 =
17. 17.644 − 497 =
18. 18.656 − 399 =
19. 19.817 − 499 =
20. 20.344 − 187 =
21. 21.870 − 629 =
22. 22.425 − 298 =
23. 23.481 − 299 =
24. 24.921 − 569 =
25. 25.795 − 297 =
26. 26.829 − 797 =
27. 27.958 − 797 =
28. 28.994 − 428 =
29. 29.706 − 448 =
30. 30.895 − 297 =
31. 31.712 − 428 =
32. 32.462 − 198 =
33. 33.714 − 598 =
34. 34.818 − 449 =
35. 35.314 − 119 =
36. 36.913 − 298 =
37. 37.891 − 697 =
38. 38.902 − 469 =
39. 39.318 − 169 =
40. 40.632 − 487 =

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