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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 627 · 40 questions
TalentJR

How to do it in your head (Round, then work): Round each number: 2-digit numbers to the nearest ten, 3-digit numbers to the nearest hundred. Do the easy sum with the round numbers. Choose the option closest to your estimate.

NameDateTime takenScore ___ / 40
  1. 1.Best estimate of 198 + 331? (a) 500 (b) 300 (c) 700
  2. 2.Best estimate of 13 × 26? (a) 3000 (b) 300 (c) 30
  3. 3.Best estimate of 776 + 531? (a) 1500 (b) 1100 (c) 1300
  4. 4.Best estimate of 280 + 814? (a) 1300 (b) 900 (c) 1100
  5. 5.Best estimate of 66 × 21? (a) 140 (b) 1400 (c) 14000
  6. 6.Best estimate of 38 × 73? (a) 2800 (b) 28000 (c) 280
  7. 7.Best estimate of 50 × 24? (a) 100 (b) 1000 (c) 10000
  8. 8.Best estimate of 737 + 126? (a) 600 (b) 1000 (c) 800
  9. 9.Best estimate of 33 × 62? (a) 18000 (b) 180 (c) 1800
  10. 10.Best estimate of 671 + 563? (a) 1100 (b) 1500 (c) 1300
  11. 11.Best estimate of 18 × 82? (a) 1600 (b) 16000 (c) 160
  12. 12.Best estimate of 165 + 282? (a) 500 (b) 700 (c) 300
  13. 13.Best estimate of 377 + 682? (a) 1100 (b) 1300 (c) 900
  14. 14.Best estimate of 56 × 76? (a) 4800 (b) 480 (c) 48000
  15. 15.Best estimate of 88 × 17? (a) 1800 (b) 180 (c) 18000
  16. 16.Best estimate of 62 × 24? (a) 1200 (b) 120 (c) 12000
  17. 17.Best estimate of 120 + 825? (a) 900 (b) 1100 (c) 700
  18. 18.Best estimate of 814 + 503? (a) 1300 (b) 1500 (c) 1100
  19. 19.Best estimate of 40 × 60? (a) 2400 (b) 240 (c) 24000
  20. 20.Best estimate of 76 × 16? (a) 16000 (b) 160 (c) 1600
  21. 21.Best estimate of 666 + 244? (a) 1100 (b) 700 (c) 900
  22. 22.Best estimate of 660 + 630? (a) 1300 (b) 1500 (c) 1100
  23. 23.Best estimate of 713 + 170? (a) 1100 (b) 900 (c) 700
  24. 24.Best estimate of 54 × 98? (a) 500 (b) 50000 (c) 5000
  25. 25.Best estimate of 24 × 56? (a) 1200 (b) 120 (c) 12000
  26. 26.Best estimate of 26 × 80? (a) 2400 (b) 24000 (c) 240
  27. 27.Best estimate of 352 + 408? (a) 600 (b) 800 (c) 1000
  28. 28.Best estimate of 172 + 161? (a) 600 (b) 200 (c) 400
  29. 29.Best estimate of 387 + 265? (a) 500 (b) 700 (c) 900
  30. 30.Best estimate of 576 + 142? (a) 700 (b) 500 (c) 900
  31. 31.Best estimate of 26 × 33? (a) 9000 (b) 90 (c) 900
  32. 32.Best estimate of 129 + 422? (a) 700 (b) 300 (c) 500
  33. 33.Best estimate of 291 + 791? (a) 1300 (b) 900 (c) 1100
  34. 34.Best estimate of 92 × 22? (a) 1800 (b) 180 (c) 18000
  35. 35.Best estimate of 479 + 680? (a) 1200 (b) 1000 (c) 1400
  36. 36.Best estimate of 53 × 53? (a) 250 (b) 2500 (c) 25000
  37. 37.Best estimate of 60 × 40? (a) 2400 (b) 24000 (c) 240
  38. 38.Best estimate of 86 × 56? (a) 540 (b) 54000 (c) 5400
  39. 39.Best estimate of 588 + 165? (a) 800 (b) 1000 (c) 600
  40. 40.Best estimate of 421 + 456? (a) 900 (b) 1100 (c) 700

Answer key

  1. 500
  2. 300
  3. 1300
  4. 1100
  5. 1400
  6. 2800
  7. 1000
  8. 800
  9. 1800
  10. 1300
  11. 1600
  12. 500
  13. 1100
  14. 4800
  15. 1800
  16. 1200
  17. 900
  18. 1300
  19. 2400
  20. 1600
  21. 900
  22. 1300
  23. 900
  24. 5000
  25. 1200
  26. 2400
  27. 800
  28. 400
  29. 700
  30. 700
  31. 900
  32. 500
  33. 1100
  34. 1800
  35. 1200
  36. 2500
  37. 2400
  38. 5400
  39. 800
  40. 900

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