3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 495 · 40 questions

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

1. 1.448 + 576 =
2. 2.272 + 375 =
3. 3.680 − 246 =
4. 4.927 − 484 =
5. 5.149 + 671 =
6. 6.913 − 155 =
7. 7.338 + 161 =
8. 8.728 − 622 =
9. 9.954 − 502 =
10. 10.953 − 588 =
11. 11.666 + 172 =
12. 12.460 + 672 =
13. 13.803 − 374 =
14. 14.750 + 285 =
15. 15.362 + 171 =
16. 16.924 − 812 =
17. 17.931 − 686 =
18. 18.571 + 149 =
19. 19.865 − 114 =
20. 20.376 + 258 =
21. 21.451 − 248 =
22. 22.436 − 246 =
23. 23.171 + 347 =
24. 24.749 + 323 =
25. 25.880 − 321 =
26. 26.579 + 629 =
27. 27.777 − 129 =
28. 28.632 − 134 =
29. 29.235 + 387 =
30. 30.600 + 489 =
31. 31.560 − 424 =
32. 32.578 − 352 =
33. 33.435 + 268 =
34. 34.464 − 238 =
35. 35.238 + 201 =
36. 36.831 − 531 =
37. 37.899 − 155 =
38. 38.735 − 574 =
39. 39.479 + 147 =
40. 40.714 − 148 =

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