Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 852 · 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. 1.817 − 399 =
2. 2.951 − 798 =
3. 3.571 − 399 =
4. 4.520 − 398 =
5. 5.695 − 668 =
6. 6.976 − 647 =
7. 7.435 − 379 =
8. 8.774 − 399 =
9. 9.573 − 197 =
10. 10.448 − 179 =
11. 11.793 − 398 =
12. 12.667 − 167 =
13. 13.980 − 648 =
14. 14.476 − 397 =
15. 15.498 − 218 =
16. 16.795 − 498 =
17. 17.817 − 579 =
18. 18.662 − 509 =
19. 19.612 − 309 =
20. 20.668 − 499 =
21. 21.876 − 698 =
22. 22.350 − 199 =
23. 23.384 − 128 =
24. 24.488 − 239 =
25. 25.923 − 597 =
26. 26.707 − 397 =
27. 27.826 − 398 =
28. 28.917 − 699 =
29. 29.966 − 127 =
30. 30.228 − 198 =
31. 31.960 − 798 =
32. 32.976 − 159 =
33. 33.704 − 399 =
34. 34.754 − 377 =
35. 35.786 − 619 =
36. 36.491 − 307 =
37. 37.452 − 218 =
38. 38.756 − 198 =
39. 39.908 − 197 =
40. 40.600 − 197 =

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