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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 883 · 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 87 × 76? (a) 720 (b) 7200 (c) 72000
  2. 2.Best estimate of 260 + 174? (a) 700 (b) 300 (c) 500
  3. 3.Best estimate of 367 + 437? (a) 600 (b) 1000 (c) 800
  4. 4.Best estimate of 94 × 30? (a) 27000 (b) 2700 (c) 270
  5. 5.Best estimate of 86 × 58? (a) 540 (b) 5400 (c) 54000
  6. 6.Best estimate of 97 × 68? (a) 70000 (b) 7000 (c) 700
  7. 7.Best estimate of 655 + 494? (a) 1400 (b) 1200 (c) 1000
  8. 8.Best estimate of 19 × 92? (a) 18000 (b) 1800 (c) 180
  9. 9.Best estimate of 19 × 81? (a) 1600 (b) 16000 (c) 160
  10. 10.Best estimate of 660 + 488? (a) 1200 (b) 1000 (c) 1400
  11. 11.Best estimate of 78 × 13? (a) 80 (b) 800 (c) 8000
  12. 12.Best estimate of 40 × 58? (a) 2400 (b) 24000 (c) 240
  13. 13.Best estimate of 44 × 31? (a) 120 (b) 1200 (c) 12000
  14. 14.Best estimate of 31 × 23? (a) 6000 (b) 600 (c) 60
  15. 15.Best estimate of 29 × 70? (a) 2100 (b) 21000 (c) 210
  16. 16.Best estimate of 753 + 836? (a) 1600 (b) 1400 (c) 1800
  17. 17.Best estimate of 798 + 424? (a) 1200 (b) 1400 (c) 1000
  18. 18.Best estimate of 12 × 74? (a) 7000 (b) 70 (c) 700
  19. 19.Best estimate of 71 × 64? (a) 420 (b) 42000 (c) 4200
  20. 20.Best estimate of 512 + 496? (a) 1000 (b) 800 (c) 1200
  21. 21.Best estimate of 61 × 40? (a) 24000 (b) 240 (c) 2400
  22. 22.Best estimate of 269 + 546? (a) 1000 (b) 600 (c) 800
  23. 23.Best estimate of 57 × 29? (a) 18000 (b) 180 (c) 1800
  24. 24.Best estimate of 840 + 778? (a) 1600 (b) 1400 (c) 1800
  25. 25.Best estimate of 76 × 64? (a) 480 (b) 4800 (c) 48000
  26. 26.Best estimate of 53 × 87? (a) 450 (b) 4500 (c) 45000
  27. 27.Best estimate of 68 × 22? (a) 14000 (b) 1400 (c) 140
  28. 28.Best estimate of 255 + 697? (a) 800 (b) 1200 (c) 1000
  29. 29.Best estimate of 44 × 77? (a) 320 (b) 32000 (c) 3200
  30. 30.Best estimate of 706 + 327? (a) 800 (b) 1200 (c) 1000
  31. 31.Best estimate of 631 + 161? (a) 800 (b) 1000 (c) 600
  32. 32.Best estimate of 652 + 180? (a) 900 (b) 1100 (c) 700
  33. 33.Best estimate of 69 × 42? (a) 280 (b) 2800 (c) 28000
  34. 34.Best estimate of 71 × 39? (a) 2800 (b) 28000 (c) 280
  35. 35.Best estimate of 599 + 427? (a) 1000 (b) 800 (c) 1200
  36. 36.Best estimate of 80 × 86? (a) 720 (b) 72000 (c) 7200
  37. 37.Best estimate of 86 × 18? (a) 18000 (b) 180 (c) 1800
  38. 38.Best estimate of 89 × 27? (a) 27000 (b) 270 (c) 2700
  39. 39.Best estimate of 628 + 831? (a) 1600 (b) 1400 (c) 1200
  40. 40.Best estimate of 32 × 86? (a) 270 (b) 2700 (c) 27000

Answer key

  1. 7200
  2. 500
  3. 800
  4. 2700
  5. 5400
  6. 7000
  7. 1200
  8. 1800
  9. 1600
  10. 1200
  11. 800
  12. 2400
  13. 1200
  14. 600
  15. 2100
  16. 1600
  17. 1200
  18. 700
  19. 4200
  20. 1000
  21. 2400
  22. 800
  23. 1800
  24. 1600
  25. 4800
  26. 4500
  27. 1400
  28. 1000
  29. 3200
  30. 1000
  31. 800
  32. 900
  33. 2800
  34. 2800
  35. 1000
  36. 7200
  37. 1800
  38. 2700
  39. 1400
  40. 2700

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