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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 614 · 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 31 × 91? (a) 27000 (b) 270 (c) 2700
  2. 2.Best estimate of 315 + 280? (a) 800 (b) 400 (c) 600
  3. 3.Best estimate of 665 + 354? (a) 900 (b) 1300 (c) 1100
  4. 4.Best estimate of 673 + 721? (a) 1400 (b) 1200 (c) 1600
  5. 5.Best estimate of 98 × 76? (a) 800 (b) 80000 (c) 8000
  6. 6.Best estimate of 631 + 216? (a) 800 (b) 1000 (c) 600
  7. 7.Best estimate of 60 × 92? (a) 54000 (b) 5400 (c) 540
  8. 8.Best estimate of 333 + 353? (a) 900 (b) 700 (c) 500
  9. 9.Best estimate of 848 + 715? (a) 1500 (b) 1300 (c) 1700
  10. 10.Best estimate of 66 × 14? (a) 7000 (b) 70 (c) 700
  11. 11.Best estimate of 39 × 21? (a) 800 (b) 80 (c) 8000
  12. 12.Best estimate of 168 + 589? (a) 1000 (b) 800 (c) 600
  13. 13.Best estimate of 399 + 300? (a) 900 (b) 700 (c) 500
  14. 14.Best estimate of 172 + 707? (a) 900 (b) 1100 (c) 700
  15. 15.Best estimate of 312 + 315? (a) 600 (b) 800 (c) 400
  16. 16.Best estimate of 614 + 278? (a) 1100 (b) 700 (c) 900
  17. 17.Best estimate of 423 + 201? (a) 600 (b) 800 (c) 400
  18. 18.Best estimate of 14 × 58? (a) 6000 (b) 600 (c) 60
  19. 19.Best estimate of 155 + 797? (a) 1200 (b) 800 (c) 1000
  20. 20.Best estimate of 27 × 76? (a) 2400 (b) 24000 (c) 240
  21. 21.Best estimate of 27 × 64? (a) 1800 (b) 18000 (c) 180
  22. 22.Best estimate of 28 × 44? (a) 1200 (b) 12000 (c) 120
  23. 23.Best estimate of 355 + 311? (a) 900 (b) 500 (c) 700
  24. 24.Best estimate of 856 + 482? (a) 1400 (b) 1200 (c) 1600
  25. 25.Best estimate of 37 × 40? (a) 16000 (b) 1600 (c) 160
  26. 26.Best estimate of 302 + 481? (a) 1000 (b) 800 (c) 600
  27. 27.Best estimate of 51 × 26? (a) 1500 (b) 15000 (c) 150
  28. 28.Best estimate of 154 + 810? (a) 1200 (b) 800 (c) 1000
  29. 29.Best estimate of 50 × 91? (a) 45000 (b) 4500 (c) 450
  30. 30.Best estimate of 197 + 257? (a) 300 (b) 700 (c) 500
  31. 31.Best estimate of 40 × 16? (a) 800 (b) 8000 (c) 80
  32. 32.Best estimate of 726 + 287? (a) 1200 (b) 800 (c) 1000
  33. 33.Best estimate of 222 + 231? (a) 400 (b) 200 (c) 600
  34. 34.Best estimate of 445 + 862? (a) 1500 (b) 1300 (c) 1100
  35. 35.Best estimate of 145 + 675? (a) 1000 (b) 800 (c) 600
  36. 36.Best estimate of 56 × 33? (a) 180 (b) 1800 (c) 18000
  37. 37.Best estimate of 54 × 97? (a) 500 (b) 50000 (c) 5000
  38. 38.Best estimate of 47 × 21? (a) 100 (b) 1000 (c) 10000
  39. 39.Best estimate of 86 × 40? (a) 3600 (b) 36000 (c) 360
  40. 40.Best estimate of 301 + 276? (a) 800 (b) 400 (c) 600

Answer key

  1. 2700
  2. 600
  3. 1100
  4. 1400
  5. 8000
  6. 800
  7. 5400
  8. 700
  9. 1500
  10. 700
  11. 800
  12. 800
  13. 700
  14. 900
  15. 600
  16. 900
  17. 600
  18. 600
  19. 1000
  20. 2400
  21. 1800
  22. 1200
  23. 700
  24. 1400
  25. 1600
  26. 800
  27. 1500
  28. 1000
  29. 4500
  30. 500
  31. 800
  32. 1000
  33. 400
  34. 1300
  35. 800
  36. 1800
  37. 5000
  38. 1000
  39. 3600
  40. 600

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