Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 353 · 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. 1.840 − 297 =
2. 2.944 − 597 =
3. 3.844 − 347 =
4. 4.987 − 399 =
5. 5.957 − 698 =
6. 6.692 − 278 =
7. 7.543 − 397 =
8. 8.927 − 399 =
9. 9.986 − 599 =
10. 10.985 − 387 =
11. 11.909 − 578 =
12. 12.409 − 197 =
13. 13.686 − 197 =
14. 14.867 − 547 =
15. 15.582 − 378 =
16. 16.963 − 349 =
17. 17.390 − 259 =
18. 18.675 − 497 =
19. 19.612 − 297 =
20. 20.414 − 189 =
21. 21.598 − 197 =
22. 22.614 − 579 =
23. 23.892 − 398 =
24. 24.888 − 589 =
25. 25.975 − 569 =
26. 26.931 − 797 =
27. 27.841 − 798 =
28. 28.631 − 397 =
29. 29.942 − 197 =
30. 30.790 − 687 =
31. 31.929 − 187 =
32. 32.399 − 199 =
33. 33.764 − 399 =
34. 34.750 − 498 =
35. 35.867 − 799 =
36. 36.475 − 298 =
37. 37.235 − 197 =
38. 38.996 − 497 =
39. 39.846 − 349 =
40. 40.734 − 238 =

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