Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 861 · 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. 1.858 − 419 =
2. 2.664 − 648 =
3. 3.945 − 299 =
4. 4.594 − 299 =
5. 5.566 − 399 =
6. 6.966 − 799 =
7. 7.816 − 639 =
8. 8.965 − 247 =
9. 9.967 − 478 =
10. 10.968 − 307 =
11. 11.867 − 409 =
12. 12.558 − 317 =
13. 13.696 − 629 =
14. 14.637 − 399 =
15. 15.738 − 519 =
16. 16.841 − 628 =
17. 17.980 − 398 =
18. 18.770 − 628 =
19. 19.460 − 397 =
20. 20.567 − 468 =
21. 21.812 − 177 =
22. 22.797 − 548 =
23. 23.892 − 369 =
24. 24.602 − 197 =
25. 25.893 − 397 =
26. 26.926 − 399 =
27. 27.774 − 697 =
28. 28.841 − 508 =
29. 29.938 − 698 =
30. 30.809 − 598 =
31. 31.786 − 397 =
32. 32.624 − 237 =
33. 33.915 − 397 =
34. 34.769 − 659 =
35. 35.815 − 697 =
36. 36.881 − 699 =
37. 37.947 − 537 =
38. 38.824 − 398 =
39. 39.735 − 299 =
40. 40.656 − 299 =

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