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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 295 · 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 53 × 73? (a) 3500 (b) 35000 (c) 350
  2. 2.Best estimate of 57 × 59? (a) 360 (b) 36000 (c) 3600
  3. 3.Best estimate of 12 × 40? (a) 400 (b) 40 (c) 4000
  4. 4.Best estimate of 49 × 38? (a) 2000 (b) 20000 (c) 200
  5. 5.Best estimate of 28 × 13? (a) 30 (b) 3000 (c) 300
  6. 6.Best estimate of 26 × 56? (a) 180 (b) 1800 (c) 18000
  7. 7.Best estimate of 724 + 585? (a) 1100 (b) 1500 (c) 1300
  8. 8.Best estimate of 357 + 310? (a) 500 (b) 900 (c) 700
  9. 9.Best estimate of 327 + 379? (a) 700 (b) 500 (c) 900
  10. 10.Best estimate of 480 + 554? (a) 1100 (b) 900 (c) 1300
  11. 11.Best estimate of 878 + 286? (a) 1200 (b) 1400 (c) 1000
  12. 12.Best estimate of 89 × 34? (a) 270 (b) 27000 (c) 2700
  13. 13.Best estimate of 642 + 663? (a) 1100 (b) 1300 (c) 1500
  14. 14.Best estimate of 711 + 600? (a) 1300 (b) 1100 (c) 1500
  15. 15.Best estimate of 237 + 232? (a) 600 (b) 400 (c) 200
  16. 16.Best estimate of 600 + 708? (a) 1500 (b) 1100 (c) 1300
  17. 17.Best estimate of 69 × 98? (a) 70000 (b) 7000 (c) 700
  18. 18.Best estimate of 149 + 729? (a) 800 (b) 1000 (c) 600
  19. 19.Best estimate of 379 + 863? (a) 1100 (b) 1500 (c) 1300
  20. 20.Best estimate of 634 + 863? (a) 1300 (b) 1700 (c) 1500
  21. 21.Best estimate of 631 + 353? (a) 1000 (b) 800 (c) 1200
  22. 22.Best estimate of 46 × 84? (a) 40000 (b) 400 (c) 4000
  23. 23.Best estimate of 88 × 80? (a) 72000 (b) 720 (c) 7200
  24. 24.Best estimate of 728 + 195? (a) 900 (b) 700 (c) 1100
  25. 25.Best estimate of 31 × 16? (a) 600 (b) 60 (c) 6000
  26. 26.Best estimate of 604 + 508? (a) 1100 (b) 1300 (c) 900
  27. 27.Best estimate of 134 + 292? (a) 200 (b) 600 (c) 400
  28. 28.Best estimate of 431 + 573? (a) 1200 (b) 1000 (c) 800
  29. 29.Best estimate of 276 + 730? (a) 1200 (b) 800 (c) 1000
  30. 30.Best estimate of 12 × 37? (a) 4000 (b) 400 (c) 40
  31. 31.Best estimate of 476 + 491? (a) 1200 (b) 1000 (c) 800
  32. 32.Best estimate of 68 × 38? (a) 2800 (b) 28000 (c) 280
  33. 33.Best estimate of 207 + 234? (a) 200 (b) 600 (c) 400
  34. 34.Best estimate of 686 + 848? (a) 1500 (b) 1700 (c) 1300
  35. 35.Best estimate of 29 × 52? (a) 15000 (b) 1500 (c) 150
  36. 36.Best estimate of 58 × 82? (a) 480 (b) 48000 (c) 4800
  37. 37.Best estimate of 492 + 240? (a) 500 (b) 900 (c) 700
  38. 38.Best estimate of 16 × 71? (a) 1400 (b) 140 (c) 14000
  39. 39.Best estimate of 419 + 849? (a) 1000 (b) 1200 (c) 1400
  40. 40.Best estimate of 66 × 50? (a) 35000 (b) 350 (c) 3500

Answer key

  1. 3500
  2. 3600
  3. 400
  4. 2000
  5. 300
  6. 1800
  7. 1300
  8. 700
  9. 700
  10. 1100
  11. 1200
  12. 2700
  13. 1300
  14. 1300
  15. 400
  16. 1300
  17. 7000
  18. 800
  19. 1300
  20. 1500
  21. 1000
  22. 4000
  23. 7200
  24. 900
  25. 600
  26. 1100
  27. 400
  28. 1000
  29. 1000
  30. 400
  31. 1000
  32. 2800
  33. 400
  34. 1500
  35. 1500
  36. 4800
  37. 700
  38. 1400
  39. 1200
  40. 3500

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