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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 202 · 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 22 × 18? (a) 4000 (b) 400 (c) 40
  2. 2.Best estimate of 67 × 49? (a) 3500 (b) 350 (c) 35000
  3. 3.Best estimate of 807 + 854? (a) 1700 (b) 1500 (c) 1900
  4. 4.Best estimate of 562 + 751? (a) 1400 (b) 1600 (c) 1200
  5. 5.Best estimate of 454 + 306? (a) 600 (b) 1000 (c) 800
  6. 6.Best estimate of 58 × 72? (a) 420 (b) 42000 (c) 4200
  7. 7.Best estimate of 86 × 94? (a) 810 (b) 81000 (c) 8100
  8. 8.Best estimate of 29 × 63? (a) 180 (b) 1800 (c) 18000
  9. 9.Best estimate of 64 × 77? (a) 4800 (b) 48000 (c) 480
  10. 10.Best estimate of 74 × 89? (a) 6300 (b) 63000 (c) 630
  11. 11.Best estimate of 44 × 44? (a) 1600 (b) 160 (c) 16000
  12. 12.Best estimate of 73 × 38? (a) 2800 (b) 280 (c) 28000
  13. 13.Best estimate of 325 + 723? (a) 1200 (b) 800 (c) 1000
  14. 14.Best estimate of 56 × 68? (a) 42000 (b) 420 (c) 4200
  15. 15.Best estimate of 97 × 97? (a) 10000 (b) 1000 (c) 100000
  16. 16.Best estimate of 48 × 57? (a) 30000 (b) 3000 (c) 300
  17. 17.Best estimate of 26 × 26? (a) 90 (b) 9000 (c) 900
  18. 18.Best estimate of 434 + 556? (a) 1000 (b) 800 (c) 1200
  19. 19.Best estimate of 64 × 40? (a) 2400 (b) 240 (c) 24000
  20. 20.Best estimate of 628 + 140? (a) 700 (b) 900 (c) 500
  21. 21.Best estimate of 27 × 79? (a) 2400 (b) 240 (c) 24000
  22. 22.Best estimate of 56 × 59? (a) 3600 (b) 360 (c) 36000
  23. 23.Best estimate of 58 × 34? (a) 18000 (b) 180 (c) 1800
  24. 24.Best estimate of 785 + 852? (a) 1900 (b) 1700 (c) 1500
  25. 25.Best estimate of 66 × 78? (a) 5600 (b) 560 (c) 56000
  26. 26.Best estimate of 649 + 345? (a) 1100 (b) 700 (c) 900
  27. 27.Best estimate of 34 × 44? (a) 1200 (b) 12000 (c) 120
  28. 28.Best estimate of 316 + 491? (a) 800 (b) 600 (c) 1000
  29. 29.Best estimate of 33 × 98? (a) 300 (b) 3000 (c) 30000
  30. 30.Best estimate of 233 + 551? (a) 1000 (b) 800 (c) 600
  31. 31.Best estimate of 257 + 674? (a) 1200 (b) 1000 (c) 800
  32. 32.Best estimate of 92 × 72? (a) 6300 (b) 630 (c) 63000
  33. 33.Best estimate of 23 × 48? (a) 10000 (b) 1000 (c) 100
  34. 34.Best estimate of 98 × 36? (a) 4000 (b) 400 (c) 40000
  35. 35.Best estimate of 676 + 278? (a) 1000 (b) 1200 (c) 800
  36. 36.Best estimate of 57 × 47? (a) 3000 (b) 30000 (c) 300
  37. 37.Best estimate of 20 × 31? (a) 6000 (b) 600 (c) 60
  38. 38.Best estimate of 90 × 76? (a) 72000 (b) 7200 (c) 720
  39. 39.Best estimate of 68 × 16? (a) 140 (b) 14000 (c) 1400
  40. 40.Best estimate of 784 + 729? (a) 1500 (b) 1300 (c) 1700

Answer key

  1. 400
  2. 3500
  3. 1700
  4. 1400
  5. 800
  6. 4200
  7. 8100
  8. 1800
  9. 4800
  10. 6300
  11. 1600
  12. 2800
  13. 1000
  14. 4200
  15. 10000
  16. 3000
  17. 900
  18. 1000
  19. 2400
  20. 700
  21. 2400
  22. 3600
  23. 1800
  24. 1700
  25. 5600
  26. 900
  27. 1200
  28. 800
  29. 3000
  30. 800
  31. 1000
  32. 6300
  33. 1000
  34. 4000
  35. 1000
  36. 3000
  37. 600
  38. 7200
  39. 1400
  40. 1500

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