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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 770 · 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 879 + 314? (a) 1000 (b) 1200 (c) 1400
  2. 2.Best estimate of 71 × 14? (a) 70 (b) 700 (c) 7000
  3. 3.Best estimate of 268 + 536? (a) 1000 (b) 800 (c) 600
  4. 4.Best estimate of 171 + 790? (a) 800 (b) 1000 (c) 1200
  5. 5.Best estimate of 870 + 694? (a) 1800 (b) 1400 (c) 1600
  6. 6.Best estimate of 26 × 69? (a) 210 (b) 21000 (c) 2100
  7. 7.Best estimate of 136 + 460? (a) 800 (b) 600 (c) 400
  8. 8.Best estimate of 370 + 496? (a) 1100 (b) 900 (c) 700
  9. 9.Best estimate of 345 + 449? (a) 700 (b) 900 (c) 500
  10. 10.Best estimate of 385 + 140? (a) 300 (b) 700 (c) 500
  11. 11.Best estimate of 822 + 755? (a) 1800 (b) 1600 (c) 1400
  12. 12.Best estimate of 86 × 72? (a) 63000 (b) 6300 (c) 630
  13. 13.Best estimate of 382 + 484? (a) 700 (b) 1100 (c) 900
  14. 14.Best estimate of 201 + 505? (a) 700 (b) 900 (c) 500
  15. 15.Best estimate of 71 × 42? (a) 2800 (b) 28000 (c) 280
  16. 16.Best estimate of 87 × 14? (a) 900 (b) 9000 (c) 90
  17. 17.Best estimate of 16 × 86? (a) 180 (b) 1800 (c) 18000
  18. 18.Best estimate of 366 + 564? (a) 1200 (b) 800 (c) 1000
  19. 19.Best estimate of 69 × 94? (a) 63000 (b) 630 (c) 6300
  20. 20.Best estimate of 636 + 574? (a) 1400 (b) 1000 (c) 1200
  21. 21.Best estimate of 510 + 188? (a) 700 (b) 500 (c) 900
  22. 22.Best estimate of 491 + 478? (a) 1000 (b) 1200 (c) 800
  23. 23.Best estimate of 283 + 168? (a) 700 (b) 300 (c) 500
  24. 24.Best estimate of 608 + 393? (a) 1000 (b) 800 (c) 1200
  25. 25.Best estimate of 64 × 59? (a) 3600 (b) 36000 (c) 360
  26. 26.Best estimate of 851 + 173? (a) 1300 (b) 1100 (c) 900
  27. 27.Best estimate of 12 × 26? (a) 3000 (b) 300 (c) 30
  28. 28.Best estimate of 365 + 362? (a) 1000 (b) 800 (c) 600
  29. 29.Best estimate of 170 + 551? (a) 1000 (b) 800 (c) 600
  30. 30.Best estimate of 716 + 231? (a) 1100 (b) 700 (c) 900
  31. 31.Best estimate of 86 × 26? (a) 27000 (b) 2700 (c) 270
  32. 32.Best estimate of 694 + 305? (a) 1200 (b) 800 (c) 1000
  33. 33.Best estimate of 298 + 325? (a) 800 (b) 400 (c) 600
  34. 34.Best estimate of 89 × 50? (a) 45000 (b) 450 (c) 4500
  35. 35.Best estimate of 27 × 49? (a) 150 (b) 15000 (c) 1500
  36. 36.Best estimate of 773 + 180? (a) 1000 (b) 1200 (c) 800
  37. 37.Best estimate of 50 × 54? (a) 250 (b) 25000 (c) 2500
  38. 38.Best estimate of 56 × 93? (a) 54000 (b) 5400 (c) 540
  39. 39.Best estimate of 73 × 69? (a) 49000 (b) 4900 (c) 490
  40. 40.Best estimate of 56 × 80? (a) 4800 (b) 48000 (c) 480

Answer key

  1. 1200
  2. 700
  3. 800
  4. 1000
  5. 1600
  6. 2100
  7. 600
  8. 900
  9. 700
  10. 500
  11. 1600
  12. 6300
  13. 900
  14. 700
  15. 2800
  16. 900
  17. 1800
  18. 1000
  19. 6300
  20. 1200
  21. 700
  22. 1000
  23. 500
  24. 1000
  25. 3600
  26. 1100
  27. 300
  28. 800
  29. 800
  30. 900
  31. 2700
  32. 1000
  33. 600
  34. 4500
  35. 1500
  36. 1000
  37. 2500
  38. 5400
  39. 4900
  40. 4800

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