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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 62 · 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 370 + 237? (a) 800 (b) 600 (c) 400
  2. 2.Best estimate of 78 × 79? (a) 64000 (b) 640 (c) 6400
  3. 3.Best estimate of 20 × 20? (a) 4000 (b) 40 (c) 400
  4. 4.Best estimate of 92 × 44? (a) 36000 (b) 360 (c) 3600
  5. 5.Best estimate of 86 × 63? (a) 540 (b) 54000 (c) 5400
  6. 6.Best estimate of 764 + 136? (a) 900 (b) 1100 (c) 700
  7. 7.Best estimate of 859 + 232? (a) 1100 (b) 1300 (c) 900
  8. 8.Best estimate of 271 + 803? (a) 1300 (b) 900 (c) 1100
  9. 9.Best estimate of 213 + 768? (a) 1000 (b) 1200 (c) 800
  10. 10.Best estimate of 93 × 73? (a) 6300 (b) 630 (c) 63000
  11. 11.Best estimate of 874 + 745? (a) 1600 (b) 1800 (c) 1400
  12. 12.Best estimate of 746 + 594? (a) 1300 (b) 1100 (c) 1500
  13. 13.Best estimate of 41 × 89? (a) 360 (b) 3600 (c) 36000
  14. 14.Best estimate of 82 × 36? (a) 320 (b) 32000 (c) 3200
  15. 15.Best estimate of 515 + 240? (a) 700 (b) 500 (c) 900
  16. 16.Best estimate of 36 × 24? (a) 8000 (b) 80 (c) 800
  17. 17.Best estimate of 686 + 848? (a) 1300 (b) 1500 (c) 1700
  18. 18.Best estimate of 64 × 76? (a) 4800 (b) 48000 (c) 480
  19. 19.Best estimate of 693 + 190? (a) 900 (b) 700 (c) 1100
  20. 20.Best estimate of 120 + 352? (a) 700 (b) 300 (c) 500
  21. 21.Best estimate of 656 + 575? (a) 1100 (b) 1500 (c) 1300
  22. 22.Best estimate of 69 × 70? (a) 4900 (b) 49000 (c) 490
  23. 23.Best estimate of 49 × 46? (a) 2500 (b) 25000 (c) 250
  24. 24.Best estimate of 18 × 18? (a) 400 (b) 4000 (c) 40
  25. 25.Best estimate of 667 + 571? (a) 1100 (b) 1500 (c) 1300
  26. 26.Best estimate of 200 + 784? (a) 1200 (b) 1000 (c) 800
  27. 27.Best estimate of 394 + 385? (a) 600 (b) 800 (c) 1000
  28. 28.Best estimate of 248 + 270? (a) 500 (b) 300 (c) 700
  29. 29.Best estimate of 54 × 90? (a) 450 (b) 4500 (c) 45000
  30. 30.Best estimate of 368 + 170? (a) 400 (b) 800 (c) 600
  31. 31.Best estimate of 28 × 86? (a) 2700 (b) 27000 (c) 270
  32. 32.Best estimate of 524 + 841? (a) 1500 (b) 1100 (c) 1300
  33. 33.Best estimate of 559 + 638? (a) 1400 (b) 1000 (c) 1200
  34. 34.Best estimate of 175 + 863? (a) 900 (b) 1100 (c) 1300
  35. 35.Best estimate of 280 + 444? (a) 700 (b) 500 (c) 900
  36. 36.Best estimate of 92 × 76? (a) 720 (b) 7200 (c) 72000
  37. 37.Best estimate of 36 × 84? (a) 32000 (b) 320 (c) 3200
  38. 38.Best estimate of 316 + 504? (a) 600 (b) 800 (c) 1000
  39. 39.Best estimate of 533 + 558? (a) 900 (b) 1300 (c) 1100
  40. 40.Best estimate of 136 + 197? (a) 300 (b) 100 (c) 500

Answer key

  1. 600
  2. 6400
  3. 400
  4. 3600
  5. 5400
  6. 900
  7. 1100
  8. 1100
  9. 1000
  10. 6300
  11. 1600
  12. 1300
  13. 3600
  14. 3200
  15. 700
  16. 800
  17. 1500
  18. 4800
  19. 900
  20. 500
  21. 1300
  22. 4900
  23. 2500
  24. 400
  25. 1300
  26. 1000
  27. 800
  28. 500
  29. 4500
  30. 600
  31. 2700
  32. 1300
  33. 1200
  34. 1100
  35. 700
  36. 7200
  37. 3200
  38. 800
  39. 1100
  40. 300

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