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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 420 · 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 97 × 19? (a) 20000 (b) 200 (c) 2000
  2. 2.Best estimate of 96 × 26? (a) 300 (b) 30000 (c) 3000
  3. 3.Best estimate of 292 + 674? (a) 1200 (b) 800 (c) 1000
  4. 4.Best estimate of 59 × 43? (a) 24000 (b) 2400 (c) 240
  5. 5.Best estimate of 738 + 253? (a) 1000 (b) 800 (c) 1200
  6. 6.Best estimate of 74 × 40? (a) 2800 (b) 28000 (c) 280
  7. 7.Best estimate of 16 × 36? (a) 8000 (b) 800 (c) 80
  8. 8.Best estimate of 60 × 57? (a) 3600 (b) 360 (c) 36000
  9. 9.Best estimate of 369 + 806? (a) 1400 (b) 1000 (c) 1200
  10. 10.Best estimate of 87 × 30? (a) 27000 (b) 2700 (c) 270
  11. 11.Best estimate of 46 × 28? (a) 15000 (b) 1500 (c) 150
  12. 12.Best estimate of 26 × 23? (a) 60 (b) 600 (c) 6000
  13. 13.Best estimate of 56 × 27? (a) 180 (b) 1800 (c) 18000
  14. 14.Best estimate of 616 + 520? (a) 1300 (b) 900 (c) 1100
  15. 15.Best estimate of 18 × 67? (a) 14000 (b) 140 (c) 1400
  16. 16.Best estimate of 680 + 152? (a) 900 (b) 1100 (c) 700
  17. 17.Best estimate of 24 × 23? (a) 400 (b) 40 (c) 4000
  18. 18.Best estimate of 777 + 737? (a) 1700 (b) 1300 (c) 1500
  19. 19.Best estimate of 49 × 66? (a) 3500 (b) 350 (c) 35000
  20. 20.Best estimate of 385 + 319? (a) 900 (b) 500 (c) 700
  21. 21.Best estimate of 767 + 855? (a) 1700 (b) 1900 (c) 1500
  22. 22.Best estimate of 41 × 77? (a) 320 (b) 3200 (c) 32000
  23. 23.Best estimate of 689 + 563? (a) 1500 (b) 1100 (c) 1300
  24. 24.Best estimate of 794 + 562? (a) 1600 (b) 1400 (c) 1200
  25. 25.Best estimate of 192 + 313? (a) 300 (b) 700 (c) 500
  26. 26.Best estimate of 69 × 41? (a) 2800 (b) 280 (c) 28000
  27. 27.Best estimate of 48 × 76? (a) 4000 (b) 400 (c) 40000
  28. 28.Best estimate of 94 × 74? (a) 6300 (b) 63000 (c) 630
  29. 29.Best estimate of 680 + 593? (a) 1500 (b) 1100 (c) 1300
  30. 30.Best estimate of 764 + 163? (a) 1200 (b) 1000 (c) 800
  31. 31.Best estimate of 735 + 526? (a) 1400 (b) 1200 (c) 1000
  32. 32.Best estimate of 92 × 27? (a) 2700 (b) 27000 (c) 270
  33. 33.Best estimate of 260 + 378? (a) 500 (b) 700 (c) 900
  34. 34.Best estimate of 68 × 64? (a) 42000 (b) 420 (c) 4200
  35. 35.Best estimate of 80 × 57? (a) 480 (b) 4800 (c) 48000
  36. 36.Best estimate of 37 × 58? (a) 240 (b) 24000 (c) 2400
  37. 37.Best estimate of 293 + 331? (a) 600 (b) 800 (c) 400
  38. 38.Best estimate of 410 + 241? (a) 400 (b) 800 (c) 600
  39. 39.Best estimate of 710 + 838? (a) 1700 (b) 1500 (c) 1300
  40. 40.Best estimate of 147 + 377? (a) 500 (b) 700 (c) 300

Answer key

  1. 2000
  2. 3000
  3. 1000
  4. 2400
  5. 1000
  6. 2800
  7. 800
  8. 3600
  9. 1200
  10. 2700
  11. 1500
  12. 600
  13. 1800
  14. 1100
  15. 1400
  16. 900
  17. 400
  18. 1500
  19. 3500
  20. 700
  21. 1700
  22. 3200
  23. 1300
  24. 1400
  25. 500
  26. 2800
  27. 4000
  28. 6300
  29. 1300
  30. 1000
  31. 1200
  32. 2700
  33. 700
  34. 4200
  35. 4800
  36. 2400
  37. 600
  38. 600
  39. 1500
  40. 500

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