Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 623 · 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. 1.489 − 307 =
2. 2.658 − 597 =
3. 3.946 − 688 =
4. 4.786 − 367 =
5. 5.815 − 607 =
6. 6.393 − 367 =
7. 7.236 − 197 =
8. 8.661 − 598 =
9. 9.637 − 569 =
10. 10.964 − 148 =
11. 11.712 − 217 =
12. 12.691 − 499 =
13. 13.994 − 449 =
14. 14.391 − 198 =
15. 15.630 − 499 =
16. 16.428 − 199 =
17. 17.903 − 499 =
18. 18.578 − 539 =
19. 19.847 − 489 =
20. 20.692 − 597 =
21. 21.931 − 798 =
22. 22.942 − 698 =
23. 23.445 − 309 =
24. 24.336 − 299 =
25. 25.520 − 469 =
26. 26.346 − 117 =
27. 27.577 − 299 =
28. 28.741 − 697 =
29. 29.480 − 299 =
30. 30.912 − 509 =
31. 31.805 − 169 =
32. 32.538 − 198 =
33. 33.369 − 199 =
34. 34.392 − 297 =
35. 35.919 − 349 =
36. 36.335 − 208 =
37. 37.761 − 697 =
38. 38.603 − 499 =
39. 39.872 − 798 =
40. 40.865 − 327 =

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