Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 800 · 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. 1.836 − 428 =
2. 2.984 − 598 =
3. 3.291 − 138 =
4. 4.931 − 598 =
5. 5.634 − 398 =
6. 6.626 − 409 =
7. 7.631 − 558 =
8. 8.632 − 497 =
9. 9.265 − 149 =
10. 10.968 − 699 =
11. 11.734 − 699 =
12. 12.688 − 498 =
13. 13.743 − 699 =
14. 14.272 − 197 =
15. 15.866 − 599 =
16. 16.690 − 459 =
17. 17.555 − 507 =
18. 18.916 − 199 =
19. 19.786 − 597 =
20. 20.831 − 597 =
21. 21.845 − 698 =
22. 22.834 − 697 =
23. 23.957 − 798 =
24. 24.604 − 538 =
25. 25.752 − 197 =
26. 26.979 − 799 =
27. 27.835 − 157 =
28. 28.847 − 647 =
29. 29.774 − 509 =
30. 30.528 − 298 =
31. 31.998 − 797 =
32. 32.947 − 798 =
33. 33.738 − 598 =
34. 34.891 − 198 =
35. 35.688 − 638 =
36. 36.561 − 397 =
37. 37.818 − 697 =
38. 38.686 − 599 =
39. 39.711 − 268 =
40. 40.543 − 397 =

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths