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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 449 · 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 60 × 33? (a) 1800 (b) 180 (c) 18000
  2. 2.Best estimate of 376 + 791? (a) 1000 (b) 1200 (c) 1400
  3. 3.Best estimate of 634 + 671? (a) 1300 (b) 1100 (c) 1500
  4. 4.Best estimate of 64 × 24? (a) 12000 (b) 1200 (c) 120
  5. 5.Best estimate of 384 + 359? (a) 600 (b) 800 (c) 1000
  6. 6.Best estimate of 438 + 528? (a) 700 (b) 1100 (c) 900
  7. 7.Best estimate of 714 + 170? (a) 900 (b) 1100 (c) 700
  8. 8.Best estimate of 469 + 301? (a) 600 (b) 1000 (c) 800
  9. 9.Best estimate of 837 + 277? (a) 900 (b) 1300 (c) 1100
  10. 10.Best estimate of 91 × 80? (a) 720 (b) 7200 (c) 72000
  11. 11.Best estimate of 126 + 730? (a) 600 (b) 800 (c) 1000
  12. 12.Best estimate of 49 × 51? (a) 25000 (b) 250 (c) 2500
  13. 13.Best estimate of 56 × 98? (a) 600 (b) 60000 (c) 6000
  14. 14.Best estimate of 36 × 53? (a) 2000 (b) 20000 (c) 200
  15. 15.Best estimate of 716 + 356? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 816 + 382? (a) 1200 (b) 1000 (c) 1400
  17. 17.Best estimate of 96 × 71? (a) 700 (b) 70000 (c) 7000
  18. 18.Best estimate of 98 × 22? (a) 200 (b) 2000 (c) 20000
  19. 19.Best estimate of 798 + 675? (a) 1500 (b) 1700 (c) 1300
  20. 20.Best estimate of 781 + 521? (a) 1300 (b) 1100 (c) 1500
  21. 21.Best estimate of 66 × 50? (a) 350 (b) 3500 (c) 35000
  22. 22.Best estimate of 668 + 785? (a) 1700 (b) 1300 (c) 1500
  23. 23.Best estimate of 485 + 270? (a) 1000 (b) 600 (c) 800
  24. 24.Best estimate of 386 + 222? (a) 400 (b) 800 (c) 600
  25. 25.Best estimate of 483 + 673? (a) 1000 (b) 1200 (c) 1400
  26. 26.Best estimate of 74 × 89? (a) 63000 (b) 630 (c) 6300
  27. 27.Best estimate of 233 + 647? (a) 600 (b) 1000 (c) 800
  28. 28.Best estimate of 14 × 58? (a) 600 (b) 60 (c) 6000
  29. 29.Best estimate of 345 + 442? (a) 900 (b) 500 (c) 700
  30. 30.Best estimate of 455 + 544? (a) 1200 (b) 800 (c) 1000
  31. 31.Best estimate of 66 × 70? (a) 49000 (b) 490 (c) 4900
  32. 32.Best estimate of 158 + 707? (a) 900 (b) 700 (c) 1100
  33. 33.Best estimate of 519 + 845? (a) 1500 (b) 1100 (c) 1300
  34. 34.Best estimate of 857 + 564? (a) 1700 (b) 1300 (c) 1500
  35. 35.Best estimate of 90 × 33? (a) 2700 (b) 270 (c) 27000
  36. 36.Best estimate of 124 + 335? (a) 600 (b) 400 (c) 200
  37. 37.Best estimate of 96 × 37? (a) 40000 (b) 4000 (c) 400
  38. 38.Best estimate of 363 + 699? (a) 1300 (b) 1100 (c) 900
  39. 39.Best estimate of 745 + 133? (a) 800 (b) 600 (c) 1000
  40. 40.Best estimate of 623 + 232? (a) 800 (b) 600 (c) 1000

Answer key

  1. 1800
  2. 1200
  3. 1300
  4. 1200
  5. 800
  6. 900
  7. 900
  8. 800
  9. 1100
  10. 7200
  11. 800
  12. 2500
  13. 6000
  14. 2000
  15. 1100
  16. 1200
  17. 7000
  18. 2000
  19. 1500
  20. 1300
  21. 3500
  22. 1500
  23. 800
  24. 600
  25. 1200
  26. 6300
  27. 800
  28. 600
  29. 700
  30. 1000
  31. 4900
  32. 900
  33. 1300
  34. 1500
  35. 2700
  36. 400
  37. 4000
  38. 1100
  39. 800
  40. 800

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