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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 994 · 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 68 × 93? (a) 630 (b) 63000 (c) 6300
  2. 2.Best estimate of 135 + 851? (a) 1000 (b) 1200 (c) 800
  3. 3.Best estimate of 626 + 244? (a) 800 (b) 1000 (c) 600
  4. 4.Best estimate of 72 × 54? (a) 3500 (b) 350 (c) 35000
  5. 5.Best estimate of 871 + 154? (a) 1100 (b) 900 (c) 1300
  6. 6.Best estimate of 96 × 28? (a) 3000 (b) 30000 (c) 300
  7. 7.Best estimate of 644 + 699? (a) 1100 (b) 1300 (c) 1500
  8. 8.Best estimate of 565 + 382? (a) 1200 (b) 1000 (c) 800
  9. 9.Best estimate of 59 × 93? (a) 540 (b) 5400 (c) 54000
  10. 10.Best estimate of 785 + 138? (a) 700 (b) 1100 (c) 900
  11. 11.Best estimate of 132 + 642? (a) 500 (b) 700 (c) 900
  12. 12.Best estimate of 98 × 21? (a) 20000 (b) 2000 (c) 200
  13. 13.Best estimate of 441 + 746? (a) 1100 (b) 1300 (c) 900
  14. 14.Best estimate of 672 + 319? (a) 1200 (b) 800 (c) 1000
  15. 15.Best estimate of 96 × 57? (a) 600 (b) 6000 (c) 60000
  16. 16.Best estimate of 170 + 193? (a) 600 (b) 400 (c) 200
  17. 17.Best estimate of 712 + 559? (a) 1500 (b) 1300 (c) 1100
  18. 18.Best estimate of 16 × 46? (a) 10000 (b) 100 (c) 1000
  19. 19.Best estimate of 123 + 490? (a) 800 (b) 400 (c) 600
  20. 20.Best estimate of 16 × 56? (a) 120 (b) 1200 (c) 12000
  21. 21.Best estimate of 230 + 608? (a) 1000 (b) 800 (c) 600
  22. 22.Best estimate of 87 × 36? (a) 3600 (b) 360 (c) 36000
  23. 23.Best estimate of 38 × 71? (a) 28000 (b) 280 (c) 2800
  24. 24.Best estimate of 66 × 36? (a) 2800 (b) 28000 (c) 280
  25. 25.Best estimate of 287 + 608? (a) 700 (b) 1100 (c) 900
  26. 26.Best estimate of 34 × 76? (a) 24000 (b) 2400 (c) 240
  27. 27.Best estimate of 360 + 793? (a) 1200 (b) 1000 (c) 1400
  28. 28.Best estimate of 14 × 27? (a) 3000 (b) 30 (c) 300
  29. 29.Best estimate of 165 + 770? (a) 1200 (b) 800 (c) 1000
  30. 30.Best estimate of 424 + 484? (a) 900 (b) 1100 (c) 700
  31. 31.Best estimate of 68 × 49? (a) 35000 (b) 350 (c) 3500
  32. 32.Best estimate of 540 + 230? (a) 900 (b) 700 (c) 500
  33. 33.Best estimate of 36 × 98? (a) 4000 (b) 400 (c) 40000
  34. 34.Best estimate of 88 × 71? (a) 6300 (b) 63000 (c) 630
  35. 35.Best estimate of 50 × 69? (a) 3500 (b) 350 (c) 35000
  36. 36.Best estimate of 589 + 251? (a) 1100 (b) 900 (c) 700
  37. 37.Best estimate of 83 × 58? (a) 4800 (b) 480 (c) 48000
  38. 38.Best estimate of 30 × 49? (a) 15000 (b) 150 (c) 1500
  39. 39.Best estimate of 131 + 851? (a) 800 (b) 1200 (c) 1000
  40. 40.Best estimate of 59 × 16? (a) 120 (b) 1200 (c) 12000

Answer key

  1. 6300
  2. 1000
  3. 800
  4. 3500
  5. 1100
  6. 3000
  7. 1300
  8. 1000
  9. 5400
  10. 900
  11. 700
  12. 2000
  13. 1100
  14. 1000
  15. 6000
  16. 400
  17. 1300
  18. 1000
  19. 600
  20. 1200
  21. 800
  22. 3600
  23. 2800
  24. 2800
  25. 900
  26. 2400
  27. 1200
  28. 300
  29. 1000
  30. 900
  31. 3500
  32. 700
  33. 4000
  34. 6300
  35. 3500
  36. 900
  37. 4800
  38. 1500
  39. 1000
  40. 1200

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