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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 573 · 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 151 + 477? (a) 500 (b) 900 (c) 700
  2. 2.Best estimate of 701 + 363? (a) 1100 (b) 900 (c) 1300
  3. 3.Best estimate of 66 × 18? (a) 14000 (b) 1400 (c) 140
  4. 4.Best estimate of 56 × 80? (a) 48000 (b) 480 (c) 4800
  5. 5.Best estimate of 151 + 860? (a) 1100 (b) 900 (c) 1300
  6. 6.Best estimate of 300 + 611? (a) 1100 (b) 700 (c) 900
  7. 7.Best estimate of 612 + 271? (a) 1100 (b) 700 (c) 900
  8. 8.Best estimate of 500 + 306? (a) 600 (b) 800 (c) 1000
  9. 9.Best estimate of 385 + 565? (a) 800 (b) 1200 (c) 1000
  10. 10.Best estimate of 24 × 69? (a) 14000 (b) 1400 (c) 140
  11. 11.Best estimate of 266 + 639? (a) 700 (b) 1100 (c) 900
  12. 12.Best estimate of 463 + 380? (a) 1100 (b) 900 (c) 700
  13. 13.Best estimate of 12 × 57? (a) 60 (b) 6000 (c) 600
  14. 14.Best estimate of 94 × 12? (a) 90 (b) 9000 (c) 900
  15. 15.Best estimate of 41 × 53? (a) 200 (b) 2000 (c) 20000
  16. 16.Best estimate of 619 + 291? (a) 700 (b) 1100 (c) 900
  17. 17.Best estimate of 30 × 44? (a) 1200 (b) 120 (c) 12000
  18. 18.Best estimate of 796 + 202? (a) 1000 (b) 1200 (c) 800
  19. 19.Best estimate of 60 × 54? (a) 300 (b) 3000 (c) 30000
  20. 20.Best estimate of 274 + 634? (a) 700 (b) 900 (c) 1100
  21. 21.Best estimate of 18 × 96? (a) 2000 (b) 20000 (c) 200
  22. 22.Best estimate of 476 + 461? (a) 800 (b) 1000 (c) 1200
  23. 23.Best estimate of 285 + 519? (a) 800 (b) 600 (c) 1000
  24. 24.Best estimate of 616 + 662? (a) 1300 (b) 1100 (c) 1500
  25. 25.Best estimate of 355 + 628? (a) 1000 (b) 1200 (c) 800
  26. 26.Best estimate of 58 × 56? (a) 360 (b) 3600 (c) 36000
  27. 27.Best estimate of 32 × 19? (a) 6000 (b) 600 (c) 60
  28. 28.Best estimate of 248 + 521? (a) 500 (b) 900 (c) 700
  29. 29.Best estimate of 21 × 77? (a) 1600 (b) 160 (c) 16000
  30. 30.Best estimate of 789 + 329? (a) 1100 (b) 900 (c) 1300
  31. 31.Best estimate of 46 × 47? (a) 25000 (b) 250 (c) 2500
  32. 32.Best estimate of 34 × 56? (a) 1800 (b) 18000 (c) 180
  33. 33.Best estimate of 66 × 23? (a) 14000 (b) 140 (c) 1400
  34. 34.Best estimate of 769 + 681? (a) 1500 (b) 1300 (c) 1700
  35. 35.Best estimate of 12 × 81? (a) 80 (b) 8000 (c) 800
  36. 36.Best estimate of 27 × 56? (a) 1800 (b) 180 (c) 18000
  37. 37.Best estimate of 735 + 275? (a) 1000 (b) 1200 (c) 800
  38. 38.Best estimate of 603 + 304? (a) 1100 (b) 700 (c) 900
  39. 39.Best estimate of 530 + 554? (a) 1300 (b) 1100 (c) 900
  40. 40.Best estimate of 809 + 774? (a) 1400 (b) 1600 (c) 1800

Answer key

  1. 700
  2. 1100
  3. 1400
  4. 4800
  5. 1100
  6. 900
  7. 900
  8. 800
  9. 1000
  10. 1400
  11. 900
  12. 900
  13. 600
  14. 900
  15. 2000
  16. 900
  17. 1200
  18. 1000
  19. 3000
  20. 900
  21. 2000
  22. 1000
  23. 800
  24. 1300
  25. 1000
  26. 3600
  27. 600
  28. 700
  29. 1600
  30. 1100
  31. 2500
  32. 1800
  33. 1400
  34. 1500
  35. 800
  36. 1800
  37. 1000
  38. 900
  39. 1100
  40. 1600

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