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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 633 · 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 87 × 53? (a) 450 (b) 45000 (c) 4500
  2. 2.Best estimate of 93 × 98? (a) 9000 (b) 900 (c) 90000
  3. 3.Best estimate of 228 + 182? (a) 600 (b) 200 (c) 400
  4. 4.Best estimate of 66 × 44? (a) 280 (b) 2800 (c) 28000
  5. 5.Best estimate of 543 + 193? (a) 700 (b) 900 (c) 500
  6. 6.Best estimate of 64 × 81? (a) 4800 (b) 48000 (c) 480
  7. 7.Best estimate of 347 + 815? (a) 900 (b) 1100 (c) 1300
  8. 8.Best estimate of 86 × 27? (a) 270 (b) 2700 (c) 27000
  9. 9.Best estimate of 344 + 476? (a) 600 (b) 1000 (c) 800
  10. 10.Best estimate of 512 + 526? (a) 1000 (b) 800 (c) 1200
  11. 11.Best estimate of 458 + 136? (a) 400 (b) 600 (c) 800
  12. 12.Best estimate of 21 × 18? (a) 4000 (b) 400 (c) 40
  13. 13.Best estimate of 76 × 61? (a) 4800 (b) 480 (c) 48000
  14. 14.Best estimate of 311 + 633? (a) 1100 (b) 900 (c) 700
  15. 15.Best estimate of 13 × 53? (a) 50 (b) 5000 (c) 500
  16. 16.Best estimate of 28 × 43? (a) 12000 (b) 120 (c) 1200
  17. 17.Best estimate of 88 × 51? (a) 4500 (b) 45000 (c) 450
  18. 18.Best estimate of 774 + 461? (a) 1100 (b) 1500 (c) 1300
  19. 19.Best estimate of 488 + 689? (a) 1000 (b) 1200 (c) 1400
  20. 20.Best estimate of 37 × 14? (a) 4000 (b) 400 (c) 40
  21. 21.Best estimate of 153 + 485? (a) 500 (b) 700 (c) 900
  22. 22.Best estimate of 31 × 50? (a) 1500 (b) 150 (c) 15000
  23. 23.Best estimate of 210 + 306? (a) 300 (b) 500 (c) 700
  24. 24.Best estimate of 86 × 98? (a) 90000 (b) 900 (c) 9000
  25. 25.Best estimate of 73 × 74? (a) 490 (b) 4900 (c) 49000
  26. 26.Best estimate of 52 × 46? (a) 2500 (b) 25000 (c) 250
  27. 27.Best estimate of 276 + 300? (a) 800 (b) 600 (c) 400
  28. 28.Best estimate of 136 + 132? (a) 200 (b) 0 (c) 400
  29. 29.Best estimate of 26 × 26? (a) 900 (b) 90 (c) 9000
  30. 30.Best estimate of 39 × 66? (a) 28000 (b) 2800 (c) 280
  31. 31.Best estimate of 468 + 175? (a) 500 (b) 900 (c) 700
  32. 32.Best estimate of 90 × 96? (a) 9000 (b) 90000 (c) 900
  33. 33.Best estimate of 31 × 31? (a) 9000 (b) 90 (c) 900
  34. 34.Best estimate of 615 + 308? (a) 900 (b) 700 (c) 1100
  35. 35.Best estimate of 14 × 74? (a) 70 (b) 700 (c) 7000
  36. 36.Best estimate of 282 + 691? (a) 1000 (b) 1200 (c) 800
  37. 37.Best estimate of 171 + 419? (a) 600 (b) 800 (c) 400
  38. 38.Best estimate of 529 + 129? (a) 800 (b) 600 (c) 400
  39. 39.Best estimate of 93 × 60? (a) 540 (b) 5400 (c) 54000
  40. 40.Best estimate of 88 × 88? (a) 8100 (b) 81000 (c) 810

Answer key

  1. 4500
  2. 9000
  3. 400
  4. 2800
  5. 700
  6. 4800
  7. 1100
  8. 2700
  9. 800
  10. 1000
  11. 600
  12. 400
  13. 4800
  14. 900
  15. 500
  16. 1200
  17. 4500
  18. 1300
  19. 1200
  20. 400
  21. 700
  22. 1500
  23. 500
  24. 9000
  25. 4900
  26. 2500
  27. 600
  28. 200
  29. 900
  30. 2800
  31. 700
  32. 9000
  33. 900
  34. 900
  35. 700
  36. 1000
  37. 600
  38. 600
  39. 5400
  40. 8100

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