3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 407 · 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. 1.589 − 411 =
2. 2.789 + 411 =
3. 3.489 − 234 =
4. 4.494 − 225 =
5. 5.939 − 421 =
6. 6.896 − 665 =
7. 7.970 − 711 =
8. 8.608 + 442 =
9. 9.428 − 131 =
10. 10.659 − 377 =
11. 11.672 − 157 =
12. 12.228 + 624 =
13. 13.819 − 519 =
14. 14.545 − 217 =
15. 15.737 − 261 =
16. 16.448 + 123 =
17. 17.735 − 241 =
18. 18.931 − 271 =
19. 19.503 + 643 =
20. 20.577 − 214 =
21. 21.519 + 502 =
22. 22.708 − 121 =
23. 23.894 − 226 =
24. 24.425 − 246 =
25. 25.723 − 196 =
26. 26.959 − 325 =
27. 27.700 + 211 =
28. 28.938 − 744 =
29. 29.744 − 179 =
30. 30.686 − 311 =
31. 31.174 + 371 =
32. 32.146 + 176 =
33. 33.766 + 388 =
34. 34.345 + 626 =
35. 35.781 + 569 =
36. 36.208 + 614 =
37. 37.148 + 349 =
38. 38.449 − 264 =
39. 39.556 + 221 =
40. 40.843 − 743 =

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