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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 905 · 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 564 + 426? (a) 1000 (b) 800 (c) 1200
  2. 2.Best estimate of 224 + 382? (a) 400 (b) 600 (c) 800
  3. 3.Best estimate of 51 × 64? (a) 3000 (b) 30000 (c) 300
  4. 4.Best estimate of 251 + 790? (a) 1300 (b) 1100 (c) 900
  5. 5.Best estimate of 93 × 37? (a) 3600 (b) 360 (c) 36000
  6. 6.Best estimate of 458 + 578? (a) 1300 (b) 900 (c) 1100
  7. 7.Best estimate of 452 + 246? (a) 500 (b) 900 (c) 700
  8. 8.Best estimate of 601 + 714? (a) 1100 (b) 1500 (c) 1300
  9. 9.Best estimate of 78 × 64? (a) 4800 (b) 480 (c) 48000
  10. 10.Best estimate of 412 + 784? (a) 1200 (b) 1400 (c) 1000
  11. 11.Best estimate of 16 × 88? (a) 18000 (b) 1800 (c) 180
  12. 12.Best estimate of 91 × 16? (a) 1800 (b) 180 (c) 18000
  13. 13.Best estimate of 612 + 476? (a) 1300 (b) 1100 (c) 900
  14. 14.Best estimate of 565 + 417? (a) 800 (b) 1000 (c) 1200
  15. 15.Best estimate of 92 × 86? (a) 81000 (b) 8100 (c) 810
  16. 16.Best estimate of 56 × 29? (a) 1800 (b) 18000 (c) 180
  17. 17.Best estimate of 529 + 151? (a) 700 (b) 900 (c) 500
  18. 18.Best estimate of 87 × 47? (a) 450 (b) 4500 (c) 45000
  19. 19.Best estimate of 43 × 96? (a) 4000 (b) 40000 (c) 400
  20. 20.Best estimate of 89 × 13? (a) 90 (b) 9000 (c) 900
  21. 21.Best estimate of 506 + 172? (a) 500 (b) 900 (c) 700
  22. 22.Best estimate of 198 + 139? (a) 300 (b) 500 (c) 100
  23. 23.Best estimate of 37 × 79? (a) 3200 (b) 32000 (c) 320
  24. 24.Best estimate of 858 + 315? (a) 1000 (b) 1400 (c) 1200
  25. 25.Best estimate of 86 × 76? (a) 7200 (b) 72000 (c) 720
  26. 26.Best estimate of 88 × 96? (a) 9000 (b) 900 (c) 90000
  27. 27.Best estimate of 56 × 76? (a) 4800 (b) 48000 (c) 480
  28. 28.Best estimate of 19 × 56? (a) 120 (b) 1200 (c) 12000
  29. 29.Best estimate of 71 × 49? (a) 35000 (b) 3500 (c) 350
  30. 30.Best estimate of 784 + 583? (a) 1600 (b) 1200 (c) 1400
  31. 31.Best estimate of 370 + 681? (a) 900 (b) 1100 (c) 1300
  32. 32.Best estimate of 862 + 740? (a) 1600 (b) 1400 (c) 1800
  33. 33.Best estimate of 49 × 71? (a) 350 (b) 3500 (c) 35000
  34. 34.Best estimate of 54 × 56? (a) 300 (b) 3000 (c) 30000
  35. 35.Best estimate of 162 + 694? (a) 900 (b) 1100 (c) 700
  36. 36.Best estimate of 36 × 89? (a) 3600 (b) 360 (c) 36000
  37. 37.Best estimate of 50 × 53? (a) 2500 (b) 25000 (c) 250
  38. 38.Best estimate of 859 + 322? (a) 1200 (b) 1000 (c) 1400
  39. 39.Best estimate of 12 × 44? (a) 400 (b) 40 (c) 4000
  40. 40.Best estimate of 78 × 93? (a) 720 (b) 7200 (c) 72000

Answer key

  1. 1000
  2. 600
  3. 3000
  4. 1100
  5. 3600
  6. 1100
  7. 700
  8. 1300
  9. 4800
  10. 1200
  11. 1800
  12. 1800
  13. 1100
  14. 1000
  15. 8100
  16. 1800
  17. 700
  18. 4500
  19. 4000
  20. 900
  21. 700
  22. 300
  23. 3200
  24. 1200
  25. 7200
  26. 9000
  27. 4800
  28. 1200
  29. 3500
  30. 1400
  31. 1100
  32. 1600
  33. 3500
  34. 3000
  35. 900
  36. 3600
  37. 2500
  38. 1200
  39. 400
  40. 7200

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