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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 388 · 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 58 × 50? (a) 300 (b) 30000 (c) 3000
  2. 2.Best estimate of 54 × 46? (a) 250 (b) 2500 (c) 25000
  3. 3.Best estimate of 844 + 182? (a) 1000 (b) 800 (c) 1200
  4. 4.Best estimate of 273 + 818? (a) 1100 (b) 900 (c) 1300
  5. 5.Best estimate of 72 × 16? (a) 140 (b) 1400 (c) 14000
  6. 6.Best estimate of 41 × 44? (a) 1600 (b) 160 (c) 16000
  7. 7.Best estimate of 96 × 51? (a) 5000 (b) 500 (c) 50000
  8. 8.Best estimate of 39 × 36? (a) 160 (b) 1600 (c) 16000
  9. 9.Best estimate of 476 + 441? (a) 900 (b) 1100 (c) 700
  10. 10.Best estimate of 20 × 81? (a) 16000 (b) 160 (c) 1600
  11. 11.Best estimate of 714 + 682? (a) 1200 (b) 1600 (c) 1400
  12. 12.Best estimate of 719 + 133? (a) 800 (b) 600 (c) 1000
  13. 13.Best estimate of 474 + 181? (a) 700 (b) 500 (c) 900
  14. 14.Best estimate of 161 + 162? (a) 400 (b) 600 (c) 200
  15. 15.Best estimate of 442 + 509? (a) 700 (b) 1100 (c) 900
  16. 16.Best estimate of 40 × 29? (a) 120 (b) 12000 (c) 1200
  17. 17.Best estimate of 712 + 572? (a) 1100 (b) 1300 (c) 1500
  18. 18.Best estimate of 464 + 832? (a) 1500 (b) 1300 (c) 1100
  19. 19.Best estimate of 87 × 89? (a) 810 (b) 8100 (c) 81000
  20. 20.Best estimate of 78 × 47? (a) 4000 (b) 400 (c) 40000
  21. 21.Best estimate of 56 × 14? (a) 600 (b) 60 (c) 6000
  22. 22.Best estimate of 343 + 808? (a) 1100 (b) 900 (c) 1300
  23. 23.Best estimate of 70 × 62? (a) 42000 (b) 4200 (c) 420
  24. 24.Best estimate of 429 + 767? (a) 1000 (b) 1400 (c) 1200
  25. 25.Best estimate of 50 × 91? (a) 450 (b) 4500 (c) 45000
  26. 26.Best estimate of 351 + 666? (a) 1300 (b) 900 (c) 1100
  27. 27.Best estimate of 16 × 58? (a) 120 (b) 12000 (c) 1200
  28. 28.Best estimate of 754 + 255? (a) 900 (b) 1300 (c) 1100
  29. 29.Best estimate of 86 × 94? (a) 81000 (b) 810 (c) 8100
  30. 30.Best estimate of 623 + 694? (a) 1100 (b) 1500 (c) 1300
  31. 31.Best estimate of 699 + 178? (a) 1100 (b) 700 (c) 900
  32. 32.Best estimate of 90 × 13? (a) 900 (b) 90 (c) 9000
  33. 33.Best estimate of 248 + 295? (a) 700 (b) 500 (c) 300
  34. 34.Best estimate of 630 + 332? (a) 1100 (b) 700 (c) 900
  35. 35.Best estimate of 22 × 67? (a) 140 (b) 14000 (c) 1400
  36. 36.Best estimate of 91 × 28? (a) 27000 (b) 2700 (c) 270
  37. 37.Best estimate of 26 × 24? (a) 60 (b) 600 (c) 6000
  38. 38.Best estimate of 751 + 324? (a) 1300 (b) 1100 (c) 900
  39. 39.Best estimate of 60 × 81? (a) 4800 (b) 480 (c) 48000
  40. 40.Best estimate of 32 × 76? (a) 24000 (b) 240 (c) 2400

Answer key

  1. 3000
  2. 2500
  3. 1000
  4. 1100
  5. 1400
  6. 1600
  7. 5000
  8. 1600
  9. 900
  10. 1600
  11. 1400
  12. 800
  13. 700
  14. 400
  15. 900
  16. 1200
  17. 1300
  18. 1300
  19. 8100
  20. 4000
  21. 600
  22. 1100
  23. 4200
  24. 1200
  25. 4500
  26. 1100
  27. 1200
  28. 1100
  29. 8100
  30. 1300
  31. 900
  32. 900
  33. 500
  34. 900
  35. 1400
  36. 2700
  37. 600
  38. 1100
  39. 4800
  40. 2400

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