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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 533 · 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 336 + 445? (a) 900 (b) 700 (c) 500
  2. 2.Best estimate of 875 + 184? (a) 1300 (b) 1100 (c) 900
  3. 3.Best estimate of 48 × 89? (a) 450 (b) 4500 (c) 45000
  4. 4.Best estimate of 50 × 73? (a) 3500 (b) 350 (c) 35000
  5. 5.Best estimate of 590 + 790? (a) 1200 (b) 1400 (c) 1600
  6. 6.Best estimate of 161 + 777? (a) 1200 (b) 800 (c) 1000
  7. 7.Best estimate of 91 × 69? (a) 6300 (b) 63000 (c) 630
  8. 8.Best estimate of 180 + 287? (a) 500 (b) 700 (c) 300
  9. 9.Best estimate of 388 + 625? (a) 1000 (b) 1200 (c) 800
  10. 10.Best estimate of 77 × 76? (a) 640 (b) 6400 (c) 64000
  11. 11.Best estimate of 851 + 481? (a) 1600 (b) 1200 (c) 1400
  12. 12.Best estimate of 84 × 77? (a) 640 (b) 6400 (c) 64000
  13. 13.Best estimate of 77 × 44? (a) 32000 (b) 3200 (c) 320
  14. 14.Best estimate of 36 × 28? (a) 1200 (b) 12000 (c) 120
  15. 15.Best estimate of 862 + 615? (a) 1500 (b) 1700 (c) 1300
  16. 16.Best estimate of 44 × 13? (a) 4000 (b) 400 (c) 40
  17. 17.Best estimate of 90 × 88? (a) 810 (b) 8100 (c) 81000
  18. 18.Best estimate of 671 + 535? (a) 1200 (b) 1000 (c) 1400
  19. 19.Best estimate of 810 + 326? (a) 1300 (b) 900 (c) 1100
  20. 20.Best estimate of 593 + 830? (a) 1600 (b) 1200 (c) 1400
  21. 21.Best estimate of 16 × 67? (a) 14000 (b) 140 (c) 1400
  22. 22.Best estimate of 430 + 726? (a) 900 (b) 1300 (c) 1100
  23. 23.Best estimate of 852 + 837? (a) 1700 (b) 1900 (c) 1500
  24. 24.Best estimate of 16 × 98? (a) 2000 (b) 20000 (c) 200
  25. 25.Best estimate of 485 + 575? (a) 1100 (b) 1300 (c) 900
  26. 26.Best estimate of 188 + 387? (a) 400 (b) 800 (c) 600
  27. 27.Best estimate of 66 × 17? (a) 140 (b) 1400 (c) 14000
  28. 28.Best estimate of 14 × 16? (a) 200 (b) 2000 (c) 20
  29. 29.Best estimate of 792 + 177? (a) 800 (b) 1200 (c) 1000
  30. 30.Best estimate of 131 + 722? (a) 800 (b) 600 (c) 1000
  31. 31.Best estimate of 86 × 58? (a) 54000 (b) 5400 (c) 540
  32. 32.Best estimate of 86 × 39? (a) 36000 (b) 360 (c) 3600
  33. 33.Best estimate of 329 + 752? (a) 900 (b) 1100 (c) 1300
  34. 34.Best estimate of 73 × 98? (a) 70000 (b) 700 (c) 7000
  35. 35.Best estimate of 44 × 86? (a) 360 (b) 36000 (c) 3600
  36. 36.Best estimate of 50 × 22? (a) 10000 (b) 100 (c) 1000
  37. 37.Best estimate of 32 × 93? (a) 2700 (b) 27000 (c) 270
  38. 38.Best estimate of 77 × 98? (a) 8000 (b) 80000 (c) 800
  39. 39.Best estimate of 18 × 30? (a) 6000 (b) 60 (c) 600
  40. 40.Best estimate of 93 × 36? (a) 36000 (b) 3600 (c) 360

Answer key

  1. 700
  2. 1100
  3. 4500
  4. 3500
  5. 1400
  6. 1000
  7. 6300
  8. 500
  9. 1000
  10. 6400
  11. 1400
  12. 6400
  13. 3200
  14. 1200
  15. 1500
  16. 400
  17. 8100
  18. 1200
  19. 1100
  20. 1400
  21. 1400
  22. 1100
  23. 1700
  24. 2000
  25. 1100
  26. 600
  27. 1400
  28. 200
  29. 1000
  30. 800
  31. 5400
  32. 3600
  33. 1100
  34. 7000
  35. 3600
  36. 1000
  37. 2700
  38. 8000
  39. 600
  40. 3600

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