3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 584 · 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. 1.709 − 252 =
2. 2.215 + 148 =
3. 3.456 − 294 =
4. 4.767 − 446 =
5. 5.513 − 141 =
6. 6.521 + 558 =
7. 7.751 + 261 =
8. 8.213 + 259 =
9. 9.466 + 617 =
10. 10.629 + 187 =
11. 11.171 + 493 =
12. 12.742 + 661 =
13. 13.255 + 119 =
14. 14.905 − 202 =
15. 15.461 − 131 =
16. 16.898 − 681 =
17. 17.431 + 212 =
18. 18.575 − 172 =
19. 19.628 + 421 =
20. 20.629 − 392 =
21. 21.580 − 292 =
22. 22.702 + 586 =
23. 23.297 + 644 =
24. 24.619 + 464 =
25. 25.855 − 149 =
26. 26.264 + 407 =
27. 27.431 − 267 =
28. 28.507 − 251 =
29. 29.469 − 286 =
30. 30.832 − 501 =
31. 31.445 + 241 =
32. 32.376 + 345 =
33. 33.457 + 643 =
34. 34.501 + 293 =
35. 35.455 − 131 =
36. 36.470 + 573 =
37. 37.562 − 123 =
38. 38.459 − 161 =
39. 39.861 − 602 =
40. 40.878 − 591 =

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