3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 56 · 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. 1.592 + 187 =
2. 2.539 + 214 =
3. 3.696 − 443 =
4. 4.455 + 371 =
5. 5.426 + 409 =
6. 6.415 − 199 =
7. 7.421 − 186 =
8. 8.227 + 261 =
9. 9.425 − 215 =
10. 10.589 + 454 =
11. 11.758 + 362 =
12. 12.318 + 466 =
13. 13.197 + 518 =
14. 14.616 + 171 =
15. 15.684 + 313 =
16. 16.495 + 222 =
17. 17.947 − 204 =
18. 18.282 + 266 =
19. 19.935 − 127 =
20. 20.798 − 218 =
21. 21.351 + 194 =
22. 22.328 + 557 =
23. 23.492 − 259 =
24. 24.516 − 173 =
25. 25.547 + 668 =
26. 26.489 + 686 =
27. 27.544 − 377 =
28. 28.620 − 272 =
29. 29.800 − 219 =
30. 30.456 − 291 =
31. 31.374 + 228 =
32. 32.203 + 567 =
33. 33.888 − 386 =
34. 34.136 + 613 =
35. 35.973 − 172 =
36. 36.511 − 359 =
37. 37.714 − 316 =
38. 38.888 − 479 =
39. 39.722 + 145 =
40. 40.303 + 176 =

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