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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 408 · 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 354 + 776? (a) 1200 (b) 1400 (c) 1000
  2. 2.Best estimate of 245 + 453? (a) 700 (b) 900 (c) 500
  3. 3.Best estimate of 67 × 43? (a) 280 (b) 28000 (c) 2800
  4. 4.Best estimate of 798 + 158? (a) 800 (b) 1200 (c) 1000
  5. 5.Best estimate of 404 + 600? (a) 1200 (b) 1000 (c) 800
  6. 6.Best estimate of 783 + 692? (a) 1700 (b) 1300 (c) 1500
  7. 7.Best estimate of 60 × 47? (a) 30000 (b) 300 (c) 3000
  8. 8.Best estimate of 606 + 397? (a) 1000 (b) 1200 (c) 800
  9. 9.Best estimate of 639 + 837? (a) 1200 (b) 1400 (c) 1600
  10. 10.Best estimate of 77 × 87? (a) 720 (b) 72000 (c) 7200
  11. 11.Best estimate of 408 + 688? (a) 900 (b) 1300 (c) 1100
  12. 12.Best estimate of 66 × 26? (a) 2100 (b) 21000 (c) 210
  13. 13.Best estimate of 50 × 63? (a) 300 (b) 30000 (c) 3000
  14. 14.Best estimate of 16 × 96? (a) 2000 (b) 20000 (c) 200
  15. 15.Best estimate of 28 × 20? (a) 600 (b) 6000 (c) 60
  16. 16.Best estimate of 196 + 521? (a) 900 (b) 700 (c) 500
  17. 17.Best estimate of 392 + 857? (a) 1100 (b) 1500 (c) 1300
  18. 18.Best estimate of 13 × 87? (a) 900 (b) 9000 (c) 90
  19. 19.Best estimate of 37 × 37? (a) 16000 (b) 160 (c) 1600
  20. 20.Best estimate of 39 × 27? (a) 1200 (b) 12000 (c) 120
  21. 21.Best estimate of 51 × 19? (a) 1000 (b) 10000 (c) 100
  22. 22.Best estimate of 44 × 18? (a) 80 (b) 8000 (c) 800
  23. 23.Best estimate of 36 × 98? (a) 4000 (b) 40000 (c) 400
  24. 24.Best estimate of 14 × 59? (a) 6000 (b) 60 (c) 600
  25. 25.Best estimate of 520 + 213? (a) 700 (b) 500 (c) 900
  26. 26.Best estimate of 16 × 50? (a) 100 (b) 1000 (c) 10000
  27. 27.Best estimate of 171 + 279? (a) 700 (b) 300 (c) 500
  28. 28.Best estimate of 553 + 644? (a) 1200 (b) 1400 (c) 1000
  29. 29.Best estimate of 877 + 185? (a) 1300 (b) 900 (c) 1100
  30. 30.Best estimate of 22 × 24? (a) 400 (b) 40 (c) 4000
  31. 31.Best estimate of 16 × 86? (a) 180 (b) 18000 (c) 1800
  32. 32.Best estimate of 73 × 46? (a) 3500 (b) 35000 (c) 350
  33. 33.Best estimate of 13 × 86? (a) 900 (b) 9000 (c) 90
  34. 34.Best estimate of 232 + 829? (a) 1000 (b) 800 (c) 1200
  35. 35.Best estimate of 51 × 39? (a) 200 (b) 2000 (c) 20000
  36. 36.Best estimate of 61 × 76? (a) 480 (b) 48000 (c) 4800
  37. 37.Best estimate of 627 + 291? (a) 700 (b) 900 (c) 1100
  38. 38.Best estimate of 215 + 241? (a) 400 (b) 200 (c) 600
  39. 39.Best estimate of 70 × 64? (a) 420 (b) 42000 (c) 4200
  40. 40.Best estimate of 671 + 301? (a) 1000 (b) 800 (c) 1200

Answer key

  1. 1200
  2. 700
  3. 2800
  4. 1000
  5. 1000
  6. 1500
  7. 3000
  8. 1000
  9. 1400
  10. 7200
  11. 1100
  12. 2100
  13. 3000
  14. 2000
  15. 600
  16. 700
  17. 1300
  18. 900
  19. 1600
  20. 1200
  21. 1000
  22. 800
  23. 4000
  24. 600
  25. 700
  26. 1000
  27. 500
  28. 1200
  29. 1100
  30. 400
  31. 1800
  32. 3500
  33. 900
  34. 1000
  35. 2000
  36. 4800
  37. 900
  38. 400
  39. 4200
  40. 1000

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