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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 913 · 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 22 × 34? (a) 6000 (b) 60 (c) 600
  2. 2.Best estimate of 46 × 18? (a) 100 (b) 1000 (c) 10000
  3. 3.Best estimate of 651 + 673? (a) 1200 (b) 1400 (c) 1600
  4. 4.Best estimate of 83 × 84? (a) 6400 (b) 64000 (c) 640
  5. 5.Best estimate of 551 + 533? (a) 900 (b) 1100 (c) 1300
  6. 6.Best estimate of 355 + 203? (a) 800 (b) 600 (c) 400
  7. 7.Best estimate of 316 + 521? (a) 1000 (b) 800 (c) 600
  8. 8.Best estimate of 633 + 238? (a) 800 (b) 1000 (c) 600
  9. 9.Best estimate of 274 + 334? (a) 800 (b) 400 (c) 600
  10. 10.Best estimate of 474 + 233? (a) 500 (b) 700 (c) 900
  11. 11.Best estimate of 92 × 53? (a) 4500 (b) 450 (c) 45000
  12. 12.Best estimate of 817 + 295? (a) 1300 (b) 900 (c) 1100
  13. 13.Best estimate of 69 × 76? (a) 5600 (b) 560 (c) 56000
  14. 14.Best estimate of 436 + 446? (a) 600 (b) 1000 (c) 800
  15. 15.Best estimate of 418 + 136? (a) 700 (b) 300 (c) 500
  16. 16.Best estimate of 376 + 782? (a) 1000 (b) 1200 (c) 1400
  17. 17.Best estimate of 452 + 376? (a) 700 (b) 900 (c) 1100
  18. 18.Best estimate of 16 × 42? (a) 800 (b) 80 (c) 8000
  19. 19.Best estimate of 420 + 726? (a) 1100 (b) 900 (c) 1300
  20. 20.Best estimate of 56 × 37? (a) 2400 (b) 240 (c) 24000
  21. 21.Best estimate of 53 × 26? (a) 1500 (b) 150 (c) 15000
  22. 22.Best estimate of 826 + 324? (a) 1100 (b) 900 (c) 1300
  23. 23.Best estimate of 39 × 72? (a) 2800 (b) 28000 (c) 280
  24. 24.Best estimate of 82 × 56? (a) 4800 (b) 48000 (c) 480
  25. 25.Best estimate of 63 × 77? (a) 4800 (b) 48000 (c) 480
  26. 26.Best estimate of 397 + 466? (a) 1100 (b) 900 (c) 700
  27. 27.Best estimate of 74 × 94? (a) 63000 (b) 630 (c) 6300
  28. 28.Best estimate of 21 × 71? (a) 140 (b) 1400 (c) 14000
  29. 29.Best estimate of 169 + 286? (a) 700 (b) 500 (c) 300
  30. 30.Best estimate of 77 × 26? (a) 2400 (b) 24000 (c) 240
  31. 31.Best estimate of 840 + 725? (a) 1700 (b) 1500 (c) 1300
  32. 32.Best estimate of 426 + 406? (a) 600 (b) 1000 (c) 800
  33. 33.Best estimate of 78 × 37? (a) 320 (b) 32000 (c) 3200
  34. 34.Best estimate of 87 × 24? (a) 1800 (b) 180 (c) 18000
  35. 35.Best estimate of 722 + 607? (a) 1100 (b) 1300 (c) 1500
  36. 36.Best estimate of 532 + 248? (a) 500 (b) 700 (c) 900
  37. 37.Best estimate of 717 + 121? (a) 600 (b) 800 (c) 1000
  38. 38.Best estimate of 94 × 28? (a) 2700 (b) 27000 (c) 270
  39. 39.Best estimate of 351 + 248? (a) 800 (b) 600 (c) 400
  40. 40.Best estimate of 49 × 18? (a) 100 (b) 10000 (c) 1000

Answer key

  1. 600
  2. 1000
  3. 1400
  4. 6400
  5. 1100
  6. 600
  7. 800
  8. 800
  9. 600
  10. 700
  11. 4500
  12. 1100
  13. 5600
  14. 800
  15. 500
  16. 1200
  17. 900
  18. 800
  19. 1100
  20. 2400
  21. 1500
  22. 1100
  23. 2800
  24. 4800
  25. 4800
  26. 900
  27. 6300
  28. 1400
  29. 500
  30. 2400
  31. 1500
  32. 800
  33. 3200
  34. 1800
  35. 1300
  36. 700
  37. 800
  38. 2700
  39. 600
  40. 1000

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