Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 781 · 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. 1.496 − 419 =
2. 2.966 − 497 =
3. 3.722 − 697 =
4. 4.872 − 499 =
5. 5.667 − 247 =
6. 6.363 − 277 =
7. 7.677 − 499 =
8. 8.939 − 598 =
9. 9.430 − 299 =
10. 10.779 − 198 =
11. 11.854 − 599 =
12. 12.765 − 699 =
13. 13.783 − 657 =
14. 14.209 − 167 =
15. 15.557 − 498 =
16. 16.903 − 638 =
17. 17.601 − 398 =
18. 18.855 − 507 =
19. 19.957 − 697 =
20. 20.888 − 798 =
21. 21.771 − 589 =
22. 22.491 − 407 =
23. 23.449 − 297 =
24. 24.630 − 199 =
25. 25.619 − 439 =
26. 26.778 − 437 =
27. 27.842 − 799 =
28. 28.596 − 519 =
29. 29.971 − 409 =
30. 30.639 − 198 =
31. 31.916 − 798 =
32. 32.223 − 187 =
33. 33.510 − 198 =
34. 34.674 − 399 =
35. 35.700 − 597 =
36. 36.817 − 508 =
37. 37.844 − 368 =
38. 38.686 − 198 =
39. 39.891 − 498 =
40. 40.986 − 397 =

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