Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 368 · 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. 1.905 − 597 =
2. 2.783 − 199 =
3. 3.913 − 799 =
4. 4.647 − 579 =
5. 5.709 − 399 =
6. 6.423 − 198 =
7. 7.795 − 357 =
8. 8.327 − 299 =
9. 9.855 − 498 =
10. 10.411 − 259 =
11. 11.363 − 297 =
12. 12.508 − 318 =
13. 13.949 − 499 =
14. 14.886 − 799 =
15. 15.692 − 597 =
16. 16.288 − 149 =
17. 17.995 − 168 =
18. 18.672 − 449 =
19. 19.807 − 439 =
20. 20.995 − 619 =
21. 21.473 − 297 =
22. 22.343 − 199 =
23. 23.349 − 198 =
24. 24.765 − 297 =
25. 25.522 − 368 =
26. 26.392 − 378 =
27. 27.342 − 229 =
28. 28.385 − 197 =
29. 29.755 − 508 =
30. 30.647 − 319 =
31. 31.840 − 498 =
32. 32.946 − 297 =
33. 33.740 − 658 =
34. 34.883 − 649 =
35. 35.736 − 288 =
36. 36.831 − 597 =
37. 37.502 − 199 =
38. 38.764 − 397 =
39. 39.607 − 558 =
40. 40.811 − 599 =

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