Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 423 · 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. 1.933 − 699 =
2. 2.724 − 488 =
3. 3.746 − 587 =
4. 4.918 − 799 =
5. 5.965 − 659 =
6. 6.974 − 647 =
7. 7.626 − 499 =
8. 8.783 − 689 =
9. 9.938 − 218 =
10. 10.907 − 629 =
11. 11.860 − 798 =
12. 12.700 − 499 =
13. 13.748 − 599 =
14. 14.327 − 297 =
15. 15.843 − 639 =
16. 16.845 − 799 =
17. 17.785 − 537 =
18. 18.712 − 498 =
19. 19.942 − 499 =
20. 20.577 − 499 =
21. 21.714 − 299 =
22. 22.768 − 579 =
23. 23.944 − 198 =
24. 24.992 − 598 =
25. 25.917 − 688 =
26. 26.900 − 629 =
27. 27.629 − 498 =
28. 28.456 − 199 =
29. 29.996 − 399 =
30. 30.780 − 697 =
31. 31.985 − 428 =
32. 32.826 − 798 =
33. 33.374 − 349 =
34. 34.751 − 648 =
35. 35.866 − 407 =
36. 36.208 − 167 =
37. 37.922 − 519 =
38. 38.811 − 599 =
39. 39.888 − 547 =
40. 40.977 − 259 =

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