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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 647 · 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 76 × 52? (a) 4000 (b) 40000 (c) 400
  2. 2.Best estimate of 821 + 492? (a) 1100 (b) 1300 (c) 1500
  3. 3.Best estimate of 30 × 17? (a) 60 (b) 6000 (c) 600
  4. 4.Best estimate of 87 × 80? (a) 7200 (b) 72000 (c) 720
  5. 5.Best estimate of 19 × 12? (a) 200 (b) 2000 (c) 20
  6. 6.Best estimate of 191 + 192? (a) 600 (b) 200 (c) 400
  7. 7.Best estimate of 773 + 757? (a) 1600 (b) 1800 (c) 1400
  8. 8.Best estimate of 68 × 40? (a) 28000 (b) 2800 (c) 280
  9. 9.Best estimate of 536 + 240? (a) 900 (b) 500 (c) 700
  10. 10.Best estimate of 681 + 306? (a) 800 (b) 1200 (c) 1000
  11. 11.Best estimate of 592 + 246? (a) 800 (b) 600 (c) 1000
  12. 12.Best estimate of 392 + 813? (a) 1000 (b) 1200 (c) 1400
  13. 13.Best estimate of 16 × 87? (a) 18000 (b) 1800 (c) 180
  14. 14.Best estimate of 467 + 563? (a) 1100 (b) 1300 (c) 900
  15. 15.Best estimate of 498 + 586? (a) 1100 (b) 900 (c) 1300
  16. 16.Best estimate of 42 × 56? (a) 2400 (b) 24000 (c) 240
  17. 17.Best estimate of 77 × 86? (a) 720 (b) 7200 (c) 72000
  18. 18.Best estimate of 270 + 423? (a) 500 (b) 700 (c) 900
  19. 19.Best estimate of 595 + 666? (a) 1500 (b) 1300 (c) 1100
  20. 20.Best estimate of 201 + 748? (a) 900 (b) 700 (c) 1100
  21. 21.Best estimate of 320 + 603? (a) 1100 (b) 700 (c) 900
  22. 22.Best estimate of 732 + 183? (a) 700 (b) 900 (c) 1100
  23. 23.Best estimate of 90 × 49? (a) 450 (b) 45000 (c) 4500
  24. 24.Best estimate of 92 × 56? (a) 540 (b) 54000 (c) 5400
  25. 25.Best estimate of 615 + 860? (a) 1500 (b) 1700 (c) 1300
  26. 26.Best estimate of 63 × 69? (a) 42000 (b) 4200 (c) 420
  27. 27.Best estimate of 96 × 37? (a) 40000 (b) 4000 (c) 400
  28. 28.Best estimate of 59 × 62? (a) 36000 (b) 360 (c) 3600
  29. 29.Best estimate of 300 + 731? (a) 800 (b) 1200 (c) 1000
  30. 30.Best estimate of 840 + 876? (a) 1900 (b) 1500 (c) 1700
  31. 31.Best estimate of 86 × 70? (a) 63000 (b) 6300 (c) 630
  32. 32.Best estimate of 795 + 365? (a) 1000 (b) 1200 (c) 1400
  33. 33.Best estimate of 14 × 76? (a) 8000 (b) 80 (c) 800
  34. 34.Best estimate of 653 + 679? (a) 1400 (b) 1600 (c) 1200
  35. 35.Best estimate of 47 × 28? (a) 150 (b) 1500 (c) 15000
  36. 36.Best estimate of 27 × 33? (a) 9000 (b) 90 (c) 900
  37. 37.Best estimate of 23 × 26? (a) 60 (b) 600 (c) 6000
  38. 38.Best estimate of 63 × 37? (a) 24000 (b) 2400 (c) 240
  39. 39.Best estimate of 76 × 58? (a) 48000 (b) 4800 (c) 480
  40. 40.Best estimate of 228 + 388? (a) 600 (b) 800 (c) 400

Answer key

  1. 4000
  2. 1300
  3. 600
  4. 7200
  5. 200
  6. 400
  7. 1600
  8. 2800
  9. 700
  10. 1000
  11. 800
  12. 1200
  13. 1800
  14. 1100
  15. 1100
  16. 2400
  17. 7200
  18. 700
  19. 1300
  20. 900
  21. 900
  22. 900
  23. 4500
  24. 5400
  25. 1500
  26. 4200
  27. 4000
  28. 3600
  29. 1000
  30. 1700
  31. 6300
  32. 1200
  33. 800
  34. 1400
  35. 1500
  36. 900
  37. 600
  38. 2400
  39. 4800
  40. 600

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