3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 493 · 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. 1.816 − 288 =
2. 2.821 − 119 =
3. 3.552 + 555 =
4. 4.787 − 194 =
5. 5.581 + 139 =
6. 6.417 − 171 =
7. 7.772 + 608 =
8. 8.891 − 692 =
9. 9.429 − 227 =
10. 10.323 + 597 =
11. 11.326 + 271 =
12. 12.478 + 439 =
13. 13.696 − 475 =
14. 14.444 + 131 =
15. 15.617 + 537 =
16. 16.301 + 683 =
17. 17.233 + 308 =
18. 18.507 + 626 =
19. 19.465 − 201 =
20. 20.426 − 309 =
21. 21.477 − 304 =
22. 22.141 + 314 =
23. 23.510 − 366 =
24. 24.314 + 112 =
25. 25.640 + 529 =
26. 26.666 − 521 =
27. 27.668 − 486 =
28. 28.145 + 217 =
29. 29.321 + 341 =
30. 30.541 + 373 =
31. 31.678 + 116 =
32. 32.159 + 355 =
33. 33.900 − 331 =
34. 34.507 − 239 =
35. 35.737 − 461 =
36. 36.777 − 209 =
37. 37.921 − 177 =
38. 38.302 + 187 =
39. 39.329 + 679 =
40. 40.598 − 217 =

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