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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 526 · 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 285 + 159? (a) 500 (b) 300 (c) 700
  2. 2.Best estimate of 53 × 77? (a) 40000 (b) 400 (c) 4000
  3. 3.Best estimate of 717 + 394? (a) 1100 (b) 1300 (c) 900
  4. 4.Best estimate of 76 × 17? (a) 160 (b) 1600 (c) 16000
  5. 5.Best estimate of 76 × 31? (a) 2400 (b) 24000 (c) 240
  6. 6.Best estimate of 308 + 249? (a) 300 (b) 500 (c) 700
  7. 7.Best estimate of 465 + 508? (a) 1200 (b) 1000 (c) 800
  8. 8.Best estimate of 137 + 655? (a) 600 (b) 800 (c) 1000
  9. 9.Best estimate of 378 + 129? (a) 700 (b) 300 (c) 500
  10. 10.Best estimate of 27 × 56? (a) 18000 (b) 180 (c) 1800
  11. 11.Best estimate of 69 × 58? (a) 420 (b) 42000 (c) 4200
  12. 12.Best estimate of 396 + 647? (a) 800 (b) 1000 (c) 1200
  13. 13.Best estimate of 88 × 90? (a) 81000 (b) 810 (c) 8100
  14. 14.Best estimate of 18 × 72? (a) 1400 (b) 14000 (c) 140
  15. 15.Best estimate of 471 + 761? (a) 1500 (b) 1100 (c) 1300
  16. 16.Best estimate of 48 × 37? (a) 20000 (b) 200 (c) 2000
  17. 17.Best estimate of 825 + 639? (a) 1200 (b) 1400 (c) 1600
  18. 18.Best estimate of 452 + 342? (a) 800 (b) 1000 (c) 600
  19. 19.Best estimate of 20 × 62? (a) 120 (b) 12000 (c) 1200
  20. 20.Best estimate of 798 + 620? (a) 1600 (b) 1400 (c) 1200
  21. 21.Best estimate of 36 × 80? (a) 320 (b) 32000 (c) 3200
  22. 22.Best estimate of 435 + 536? (a) 1100 (b) 700 (c) 900
  23. 23.Best estimate of 420 + 186? (a) 800 (b) 400 (c) 600
  24. 24.Best estimate of 424 + 519? (a) 900 (b) 700 (c) 1100
  25. 25.Best estimate of 60 × 26? (a) 1800 (b) 18000 (c) 180
  26. 26.Best estimate of 351 + 370? (a) 1000 (b) 600 (c) 800
  27. 27.Best estimate of 859 + 743? (a) 1400 (b) 1800 (c) 1600
  28. 28.Best estimate of 238 + 297? (a) 500 (b) 700 (c) 300
  29. 29.Best estimate of 788 + 676? (a) 1700 (b) 1500 (c) 1300
  30. 30.Best estimate of 48 × 73? (a) 3500 (b) 35000 (c) 350
  31. 31.Best estimate of 734 + 547? (a) 1200 (b) 1400 (c) 1000
  32. 32.Best estimate of 526 + 585? (a) 1100 (b) 900 (c) 1300
  33. 33.Best estimate of 78 × 67? (a) 560 (b) 5600 (c) 56000
  34. 34.Best estimate of 31 × 22? (a) 600 (b) 60 (c) 6000
  35. 35.Best estimate of 368 + 172? (a) 400 (b) 800 (c) 600
  36. 36.Best estimate of 16 × 88? (a) 1800 (b) 18000 (c) 180
  37. 37.Best estimate of 20 × 76? (a) 160 (b) 16000 (c) 1600
  38. 38.Best estimate of 98 × 13? (a) 1000 (b) 10000 (c) 100
  39. 39.Best estimate of 235 + 617? (a) 600 (b) 1000 (c) 800
  40. 40.Best estimate of 77 × 69? (a) 560 (b) 56000 (c) 5600

Answer key

  1. 500
  2. 4000
  3. 1100
  4. 1600
  5. 2400
  6. 500
  7. 1000
  8. 800
  9. 500
  10. 1800
  11. 4200
  12. 1000
  13. 8100
  14. 1400
  15. 1300
  16. 2000
  17. 1400
  18. 800
  19. 1200
  20. 1400
  21. 3200
  22. 900
  23. 600
  24. 900
  25. 1800
  26. 800
  27. 1600
  28. 500
  29. 1500
  30. 3500
  31. 1200
  32. 1100
  33. 5600
  34. 600
  35. 600
  36. 1800
  37. 1600
  38. 1000
  39. 800
  40. 5600

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