Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 658 · 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 − 319 =
2. 2.712 − 689 =
3. 3.872 − 547 =
4. 4.740 − 399 =
5. 5.387 − 269 =
6. 6.405 − 267 =
7. 7.461 − 297 =
8. 8.617 − 567 =
9. 9.425 − 198 =
10. 10.748 − 179 =
11. 11.366 − 299 =
12. 12.580 − 487 =
13. 13.554 − 399 =
14. 14.381 − 228 =
15. 15.839 − 179 =
16. 16.901 − 309 =
17. 17.729 − 617 =
18. 18.968 − 488 =
19. 19.823 − 799 =
20. 20.869 − 299 =
21. 21.593 − 287 =
22. 22.623 − 379 =
23. 23.832 − 628 =
24. 24.689 − 199 =
25. 25.860 − 517 =
26. 26.610 − 539 =
27. 27.780 − 398 =
28. 28.731 − 569 =
29. 29.661 − 399 =
30. 30.935 − 198 =
31. 31.460 − 389 =
32. 32.858 − 699 =
33. 33.845 − 469 =
34. 34.968 − 697 =
35. 35.536 − 497 =
36. 36.584 − 289 =
37. 37.712 − 699 =
38. 38.454 − 397 =
39. 39.728 − 177 =
40. 40.767 − 699 =

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