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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 613 · 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 448 + 445? (a) 1000 (b) 600 (c) 800
  2. 2.Best estimate of 776 + 549? (a) 1300 (b) 1100 (c) 1500
  3. 3.Best estimate of 20 × 83? (a) 160 (b) 1600 (c) 16000
  4. 4.Best estimate of 187 + 249? (a) 400 (b) 600 (c) 200
  5. 5.Best estimate of 40 × 53? (a) 200 (b) 20000 (c) 2000
  6. 6.Best estimate of 421 + 754? (a) 1200 (b) 1000 (c) 1400
  7. 7.Best estimate of 649 + 360? (a) 800 (b) 1200 (c) 1000
  8. 8.Best estimate of 73 × 98? (a) 700 (b) 7000 (c) 70000
  9. 9.Best estimate of 214 + 282? (a) 500 (b) 300 (c) 700
  10. 10.Best estimate of 73 × 23? (a) 1400 (b) 14000 (c) 140
  11. 11.Best estimate of 46 × 23? (a) 1000 (b) 10000 (c) 100
  12. 12.Best estimate of 80 × 98? (a) 800 (b) 80000 (c) 8000
  13. 13.Best estimate of 834 + 371? (a) 1400 (b) 1200 (c) 1000
  14. 14.Best estimate of 706 + 323? (a) 1200 (b) 1000 (c) 800
  15. 15.Best estimate of 19 × 26? (a) 6000 (b) 600 (c) 60
  16. 16.Best estimate of 66 × 26? (a) 210 (b) 21000 (c) 2100
  17. 17.Best estimate of 73 × 60? (a) 42000 (b) 420 (c) 4200
  18. 18.Best estimate of 167 + 544? (a) 700 (b) 900 (c) 500
  19. 19.Best estimate of 573 + 838? (a) 1600 (b) 1200 (c) 1400
  20. 20.Best estimate of 33 × 23? (a) 600 (b) 60 (c) 6000
  21. 21.Best estimate of 570 + 710? (a) 1500 (b) 1300 (c) 1100
  22. 22.Best estimate of 162 + 211? (a) 600 (b) 200 (c) 400
  23. 23.Best estimate of 660 + 506? (a) 1200 (b) 1400 (c) 1000
  24. 24.Best estimate of 80 × 21? (a) 1600 (b) 16000 (c) 160
  25. 25.Best estimate of 14 × 16? (a) 200 (b) 2000 (c) 20
  26. 26.Best estimate of 83 × 62? (a) 480 (b) 48000 (c) 4800
  27. 27.Best estimate of 402 + 309? (a) 700 (b) 500 (c) 900
  28. 28.Best estimate of 60 × 60? (a) 36000 (b) 3600 (c) 360
  29. 29.Best estimate of 609 + 251? (a) 1100 (b) 700 (c) 900
  30. 30.Best estimate of 70 × 98? (a) 7000 (b) 70000 (c) 700
  31. 31.Best estimate of 20 × 21? (a) 400 (b) 40 (c) 4000
  32. 32.Best estimate of 51 × 70? (a) 3500 (b) 35000 (c) 350
  33. 33.Best estimate of 96 × 86? (a) 900 (b) 9000 (c) 90000
  34. 34.Best estimate of 321 + 859? (a) 1400 (b) 1000 (c) 1200
  35. 35.Best estimate of 20 × 26? (a) 60 (b) 600 (c) 6000
  36. 36.Best estimate of 66 × 14? (a) 7000 (b) 700 (c) 70
  37. 37.Best estimate of 72 × 86? (a) 6300 (b) 630 (c) 63000
  38. 38.Best estimate of 329 + 169? (a) 300 (b) 500 (c) 700
  39. 39.Best estimate of 162 + 695? (a) 700 (b) 900 (c) 1100
  40. 40.Best estimate of 378 + 594? (a) 1000 (b) 1200 (c) 800

Answer key

  1. 800
  2. 1300
  3. 1600
  4. 400
  5. 2000
  6. 1200
  7. 1000
  8. 7000
  9. 500
  10. 1400
  11. 1000
  12. 8000
  13. 1200
  14. 1000
  15. 600
  16. 2100
  17. 4200
  18. 700
  19. 1400
  20. 600
  21. 1300
  22. 400
  23. 1200
  24. 1600
  25. 200
  26. 4800
  27. 700
  28. 3600
  29. 900
  30. 7000
  31. 400
  32. 3500
  33. 9000
  34. 1200
  35. 600
  36. 700
  37. 6300
  38. 500
  39. 900
  40. 1000

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