Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 640 · 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. 1.537 − 177 =
2. 2.849 − 797 =
3. 3.807 − 397 =
4. 4.996 − 798 =
5. 5.742 − 597 =
6. 6.426 − 399 =
7. 7.948 − 488 =
8. 8.529 − 399 =
9. 9.773 − 298 =
10. 10.846 − 417 =
11. 11.617 − 599 =
12. 12.897 − 299 =
13. 13.665 − 569 =
14. 14.779 − 699 =
15. 15.750 − 399 =
16. 16.771 − 399 =
17. 17.557 − 358 =
18. 18.639 − 139 =
19. 19.773 − 398 =
20. 20.904 − 799 =
21. 21.447 − 158 =
22. 22.918 − 659 =
23. 23.651 − 497 =
24. 24.562 − 497 =
25. 25.861 − 449 =
26. 26.932 − 699 =
27. 27.274 − 158 =
28. 28.643 − 299 =
29. 29.630 − 397 =
30. 30.834 − 558 =
31. 31.670 − 577 =
32. 32.574 − 447 =
33. 33.771 − 699 =
34. 34.968 − 798 =
35. 35.699 − 427 =
36. 36.351 − 268 =
37. 37.190 − 117 =
38. 38.393 − 308 =
39. 39.897 − 659 =
40. 40.701 − 298 =

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