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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 277 · 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 865 + 829? (a) 1700 (b) 1500 (c) 1900
  2. 2.Best estimate of 809 + 696? (a) 1500 (b) 1300 (c) 1700
  3. 3.Best estimate of 40 × 36? (a) 1600 (b) 16000 (c) 160
  4. 4.Best estimate of 138 + 247? (a) 500 (b) 100 (c) 300
  5. 5.Best estimate of 16 × 52? (a) 10000 (b) 100 (c) 1000
  6. 6.Best estimate of 83 × 23? (a) 160 (b) 1600 (c) 16000
  7. 7.Best estimate of 28 × 18? (a) 600 (b) 60 (c) 6000
  8. 8.Best estimate of 47 × 39? (a) 20000 (b) 200 (c) 2000
  9. 9.Best estimate of 33 × 72? (a) 21000 (b) 210 (c) 2100
  10. 10.Best estimate of 44 × 56? (a) 2400 (b) 240 (c) 24000
  11. 11.Best estimate of 64 × 36? (a) 24000 (b) 2400 (c) 240
  12. 12.Best estimate of 36 × 13? (a) 4000 (b) 40 (c) 400
  13. 13.Best estimate of 54 × 57? (a) 300 (b) 30000 (c) 3000
  14. 14.Best estimate of 32 × 96? (a) 30000 (b) 300 (c) 3000
  15. 15.Best estimate of 606 + 341? (a) 700 (b) 900 (c) 1100
  16. 16.Best estimate of 94 × 78? (a) 7200 (b) 720 (c) 72000
  17. 17.Best estimate of 470 + 192? (a) 500 (b) 700 (c) 900
  18. 18.Best estimate of 37 × 96? (a) 400 (b) 40000 (c) 4000
  19. 19.Best estimate of 44 × 36? (a) 160 (b) 16000 (c) 1600
  20. 20.Best estimate of 259 + 626? (a) 700 (b) 1100 (c) 900
  21. 21.Best estimate of 192 + 500? (a) 500 (b) 700 (c) 900
  22. 22.Best estimate of 76 × 46? (a) 4000 (b) 400 (c) 40000
  23. 23.Best estimate of 18 × 97? (a) 2000 (b) 20000 (c) 200
  24. 24.Best estimate of 584 + 148? (a) 900 (b) 500 (c) 700
  25. 25.Best estimate of 337 + 738? (a) 1200 (b) 1000 (c) 800
  26. 26.Best estimate of 312 + 442? (a) 500 (b) 700 (c) 900
  27. 27.Best estimate of 96 × 90? (a) 9000 (b) 900 (c) 90000
  28. 28.Best estimate of 672 + 621? (a) 1300 (b) 1500 (c) 1100
  29. 29.Best estimate of 656 + 443? (a) 1100 (b) 900 (c) 1300
  30. 30.Best estimate of 78 × 48? (a) 4000 (b) 40000 (c) 400
  31. 31.Best estimate of 43 × 98? (a) 400 (b) 4000 (c) 40000
  32. 32.Best estimate of 68 × 58? (a) 42000 (b) 4200 (c) 420
  33. 33.Best estimate of 80 × 80? (a) 6400 (b) 640 (c) 64000
  34. 34.Best estimate of 478 + 399? (a) 900 (b) 1100 (c) 700
  35. 35.Best estimate of 161 + 338? (a) 300 (b) 500 (c) 700
  36. 36.Best estimate of 512 + 528? (a) 1000 (b) 800 (c) 1200
  37. 37.Best estimate of 149 + 308? (a) 600 (b) 200 (c) 400
  38. 38.Best estimate of 36 × 54? (a) 2000 (b) 200 (c) 20000
  39. 39.Best estimate of 80 × 44? (a) 320 (b) 32000 (c) 3200
  40. 40.Best estimate of 686 + 787? (a) 1700 (b) 1500 (c) 1300

Answer key

  1. 1700
  2. 1500
  3. 1600
  4. 300
  5. 1000
  6. 1600
  7. 600
  8. 2000
  9. 2100
  10. 2400
  11. 2400
  12. 400
  13. 3000
  14. 3000
  15. 900
  16. 7200
  17. 700
  18. 4000
  19. 1600
  20. 900
  21. 700
  22. 4000
  23. 2000
  24. 700
  25. 1000
  26. 700
  27. 9000
  28. 1300
  29. 1100
  30. 4000
  31. 4000
  32. 4200
  33. 6400
  34. 900
  35. 500
  36. 1000
  37. 400
  38. 2000
  39. 3200
  40. 1500

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