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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 728 · 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 738 + 810? (a) 1700 (b) 1300 (c) 1500
  2. 2.Best estimate of 34 × 29? (a) 900 (b) 90 (c) 9000
  3. 3.Best estimate of 29 × 16? (a) 600 (b) 60 (c) 6000
  4. 4.Best estimate of 151 + 392? (a) 600 (b) 800 (c) 400
  5. 5.Best estimate of 26 × 56? (a) 1800 (b) 180 (c) 18000
  6. 6.Best estimate of 66 × 50? (a) 35000 (b) 3500 (c) 350
  7. 7.Best estimate of 51 × 58? (a) 300 (b) 3000 (c) 30000
  8. 8.Best estimate of 629 + 344? (a) 700 (b) 1100 (c) 900
  9. 9.Best estimate of 649 + 639? (a) 1200 (b) 1400 (c) 1000
  10. 10.Best estimate of 70 × 53? (a) 35000 (b) 3500 (c) 350
  11. 11.Best estimate of 374 + 612? (a) 1200 (b) 800 (c) 1000
  12. 12.Best estimate of 191 + 227? (a) 600 (b) 400 (c) 200
  13. 13.Best estimate of 28 × 22? (a) 6000 (b) 600 (c) 60
  14. 14.Best estimate of 87 × 74? (a) 63000 (b) 6300 (c) 630
  15. 15.Best estimate of 33 × 57? (a) 18000 (b) 180 (c) 1800
  16. 16.Best estimate of 799 + 533? (a) 1300 (b) 1100 (c) 1500
  17. 17.Best estimate of 416 + 703? (a) 900 (b) 1100 (c) 1300
  18. 18.Best estimate of 653 + 847? (a) 1300 (b) 1500 (c) 1700
  19. 19.Best estimate of 743 + 292? (a) 1200 (b) 800 (c) 1000
  20. 20.Best estimate of 28 × 78? (a) 240 (b) 24000 (c) 2400
  21. 21.Best estimate of 36 × 58? (a) 2400 (b) 24000 (c) 240
  22. 22.Best estimate of 564 + 201? (a) 800 (b) 1000 (c) 600
  23. 23.Best estimate of 19 × 48? (a) 1000 (b) 10000 (c) 100
  24. 24.Best estimate of 18 × 23? (a) 400 (b) 4000 (c) 40
  25. 25.Best estimate of 266 + 149? (a) 200 (b) 400 (c) 600
  26. 26.Best estimate of 625 + 787? (a) 1400 (b) 1200 (c) 1600
  27. 27.Best estimate of 42 × 66? (a) 28000 (b) 2800 (c) 280
  28. 28.Best estimate of 66 × 89? (a) 630 (b) 6300 (c) 63000
  29. 29.Best estimate of 880 + 737? (a) 1600 (b) 1800 (c) 1400
  30. 30.Best estimate of 783 + 272? (a) 1300 (b) 900 (c) 1100
  31. 31.Best estimate of 196 + 186? (a) 400 (b) 600 (c) 200
  32. 32.Best estimate of 43 × 56? (a) 240 (b) 2400 (c) 24000
  33. 33.Best estimate of 540 + 633? (a) 1300 (b) 900 (c) 1100
  34. 34.Best estimate of 316 + 428? (a) 700 (b) 900 (c) 500
  35. 35.Best estimate of 311 + 378? (a) 700 (b) 500 (c) 900
  36. 36.Best estimate of 56 × 37? (a) 24000 (b) 240 (c) 2400
  37. 37.Best estimate of 391 + 523? (a) 900 (b) 1100 (c) 700
  38. 38.Best estimate of 451 + 569? (a) 900 (b) 1100 (c) 1300
  39. 39.Best estimate of 17 × 92? (a) 1800 (b) 18000 (c) 180
  40. 40.Best estimate of 47 × 81? (a) 4000 (b) 40000 (c) 400

Answer key

  1. 1500
  2. 900
  3. 600
  4. 600
  5. 1800
  6. 3500
  7. 3000
  8. 900
  9. 1200
  10. 3500
  11. 1000
  12. 400
  13. 600
  14. 6300
  15. 1800
  16. 1300
  17. 1100
  18. 1500
  19. 1000
  20. 2400
  21. 2400
  22. 800
  23. 1000
  24. 400
  25. 400
  26. 1400
  27. 2800
  28. 6300
  29. 1600
  30. 1100
  31. 400
  32. 2400
  33. 1100
  34. 700
  35. 700
  36. 2400
  37. 900
  38. 1100
  39. 1800
  40. 4000

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