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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 904 · 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 704 + 837? (a) 1700 (b) 1500 (c) 1300
  2. 2.Best estimate of 142 + 566? (a) 900 (b) 500 (c) 700
  3. 3.Best estimate of 46 × 67? (a) 350 (b) 35000 (c) 3500
  4. 4.Best estimate of 552 + 726? (a) 1300 (b) 1100 (c) 1500
  5. 5.Best estimate of 26 × 13? (a) 300 (b) 3000 (c) 30
  6. 6.Best estimate of 64 × 20? (a) 1200 (b) 12000 (c) 120
  7. 7.Best estimate of 131 + 624? (a) 700 (b) 900 (c) 500
  8. 8.Best estimate of 599 + 145? (a) 900 (b) 500 (c) 700
  9. 9.Best estimate of 77 × 36? (a) 3200 (b) 32000 (c) 320
  10. 10.Best estimate of 78 × 76? (a) 6400 (b) 64000 (c) 640
  11. 11.Best estimate of 51 × 29? (a) 1500 (b) 15000 (c) 150
  12. 12.Best estimate of 560 + 398? (a) 1000 (b) 1200 (c) 800
  13. 13.Best estimate of 28 × 83? (a) 2400 (b) 240 (c) 24000
  14. 14.Best estimate of 459 + 285? (a) 600 (b) 1000 (c) 800
  15. 15.Best estimate of 587 + 826? (a) 1200 (b) 1600 (c) 1400
  16. 16.Best estimate of 199 + 540? (a) 700 (b) 900 (c) 500
  17. 17.Best estimate of 514 + 142? (a) 800 (b) 600 (c) 400
  18. 18.Best estimate of 727 + 519? (a) 1200 (b) 1400 (c) 1000
  19. 19.Best estimate of 66 × 24? (a) 140 (b) 1400 (c) 14000
  20. 20.Best estimate of 615 + 428? (a) 1000 (b) 1200 (c) 800
  21. 21.Best estimate of 164 + 804? (a) 800 (b) 1000 (c) 1200
  22. 22.Best estimate of 804 + 184? (a) 800 (b) 1200 (c) 1000
  23. 23.Best estimate of 736 + 363? (a) 1100 (b) 1300 (c) 900
  24. 24.Best estimate of 295 + 261? (a) 800 (b) 600 (c) 400
  25. 25.Best estimate of 14 × 36? (a) 4000 (b) 400 (c) 40
  26. 26.Best estimate of 38 × 26? (a) 12000 (b) 120 (c) 1200
  27. 27.Best estimate of 875 + 463? (a) 1200 (b) 1600 (c) 1400
  28. 28.Best estimate of 66 × 73? (a) 49000 (b) 490 (c) 4900
  29. 29.Best estimate of 64 × 16? (a) 1200 (b) 12000 (c) 120
  30. 30.Best estimate of 279 + 738? (a) 800 (b) 1000 (c) 1200
  31. 31.Best estimate of 96 × 64? (a) 60000 (b) 600 (c) 6000
  32. 32.Best estimate of 78 × 27? (a) 2400 (b) 240 (c) 24000
  33. 33.Best estimate of 29 × 89? (a) 270 (b) 2700 (c) 27000
  34. 34.Best estimate of 24 × 59? (a) 12000 (b) 120 (c) 1200
  35. 35.Best estimate of 832 + 377? (a) 1200 (b) 1000 (c) 1400
  36. 36.Best estimate of 380 + 777? (a) 1000 (b) 1200 (c) 1400
  37. 37.Best estimate of 616 + 742? (a) 1300 (b) 1100 (c) 1500
  38. 38.Best estimate of 729 + 265? (a) 1000 (b) 800 (c) 1200
  39. 39.Best estimate of 285 + 595? (a) 900 (b) 1100 (c) 700
  40. 40.Best estimate of 63 × 76? (a) 4800 (b) 48000 (c) 480

Answer key

  1. 1500
  2. 700
  3. 3500
  4. 1300
  5. 300
  6. 1200
  7. 700
  8. 700
  9. 3200
  10. 6400
  11. 1500
  12. 1000
  13. 2400
  14. 800
  15. 1400
  16. 700
  17. 600
  18. 1200
  19. 1400
  20. 1000
  21. 1000
  22. 1000
  23. 1100
  24. 600
  25. 400
  26. 1200
  27. 1400
  28. 4900
  29. 1200
  30. 1000
  31. 6000
  32. 2400
  33. 2700
  34. 1200
  35. 1200
  36. 1200
  37. 1300
  38. 1000
  39. 900
  40. 4800

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