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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 652 · 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 131 + 807? (a) 700 (b) 900 (c) 1100
  2. 2.Best estimate of 126 + 268? (a) 200 (b) 600 (c) 400
  3. 3.Best estimate of 56 × 67? (a) 420 (b) 42000 (c) 4200
  4. 4.Best estimate of 603 + 770? (a) 1600 (b) 1200 (c) 1400
  5. 5.Best estimate of 57 × 37? (a) 2400 (b) 24000 (c) 240
  6. 6.Best estimate of 370 + 440? (a) 800 (b) 600 (c) 1000
  7. 7.Best estimate of 877 + 332? (a) 1400 (b) 1000 (c) 1200
  8. 8.Best estimate of 261 + 322? (a) 800 (b) 600 (c) 400
  9. 9.Best estimate of 565 + 472? (a) 900 (b) 1300 (c) 1100
  10. 10.Best estimate of 331 + 373? (a) 900 (b) 500 (c) 700
  11. 11.Best estimate of 571 + 128? (a) 500 (b) 700 (c) 900
  12. 12.Best estimate of 293 + 683? (a) 800 (b) 1200 (c) 1000
  13. 13.Best estimate of 61 × 81? (a) 4800 (b) 480 (c) 48000
  14. 14.Best estimate of 123 + 536? (a) 800 (b) 400 (c) 600
  15. 15.Best estimate of 59 × 73? (a) 420 (b) 42000 (c) 4200
  16. 16.Best estimate of 189 + 534? (a) 900 (b) 500 (c) 700
  17. 17.Best estimate of 169 + 182? (a) 600 (b) 200 (c) 400
  18. 18.Best estimate of 96 × 33? (a) 30000 (b) 300 (c) 3000
  19. 19.Best estimate of 843 + 783? (a) 1800 (b) 1600 (c) 1400
  20. 20.Best estimate of 56 × 23? (a) 12000 (b) 1200 (c) 120
  21. 21.Best estimate of 830 + 851? (a) 1500 (b) 1700 (c) 1900
  22. 22.Best estimate of 14 × 17? (a) 20 (b) 2000 (c) 200
  23. 23.Best estimate of 251 + 842? (a) 900 (b) 1300 (c) 1100
  24. 24.Best estimate of 96 × 79? (a) 80000 (b) 800 (c) 8000
  25. 25.Best estimate of 46 × 46? (a) 250 (b) 2500 (c) 25000
  26. 26.Best estimate of 160 + 342? (a) 700 (b) 300 (c) 500
  27. 27.Best estimate of 21 × 36? (a) 80 (b) 800 (c) 8000
  28. 28.Best estimate of 80 × 92? (a) 72000 (b) 720 (c) 7200
  29. 29.Best estimate of 59 × 24? (a) 120 (b) 1200 (c) 12000
  30. 30.Best estimate of 460 + 508? (a) 1200 (b) 1000 (c) 800
  31. 31.Best estimate of 43 × 46? (a) 20000 (b) 2000 (c) 200
  32. 32.Best estimate of 86 × 66? (a) 630 (b) 6300 (c) 63000
  33. 33.Best estimate of 187 + 556? (a) 1000 (b) 600 (c) 800
  34. 34.Best estimate of 48 × 70? (a) 350 (b) 3500 (c) 35000
  35. 35.Best estimate of 855 + 622? (a) 1700 (b) 1500 (c) 1300
  36. 36.Best estimate of 520 + 677? (a) 1400 (b) 1200 (c) 1000
  37. 37.Best estimate of 215 + 383? (a) 600 (b) 400 (c) 800
  38. 38.Best estimate of 199 + 509? (a) 500 (b) 900 (c) 700
  39. 39.Best estimate of 414 + 125? (a) 300 (b) 500 (c) 700
  40. 40.Best estimate of 161 + 584? (a) 1000 (b) 600 (c) 800

Answer key

  1. 900
  2. 400
  3. 4200
  4. 1400
  5. 2400
  6. 800
  7. 1200
  8. 600
  9. 1100
  10. 700
  11. 700
  12. 1000
  13. 4800
  14. 600
  15. 4200
  16. 700
  17. 400
  18. 3000
  19. 1600
  20. 1200
  21. 1700
  22. 200
  23. 1100
  24. 8000
  25. 2500
  26. 500
  27. 800
  28. 7200
  29. 1200
  30. 1000
  31. 2000
  32. 6300
  33. 800
  34. 3500
  35. 1500
  36. 1200
  37. 600
  38. 700
  39. 500
  40. 800

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