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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 535 · 40 questions
TalentJR

How to do it in your head (Guess, divide, average): Division: round the divisor to the nearest ten and find the closest multiple of it. Square root: guess the nearest whole root, then divide the number by your guess. Average the guess and the answer of the division, and round to 1 decimal place.

NameDateTime takenScore ___ / 40
  1. 1.√78 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.8
  2. 2.Best estimate of 5046 ÷ 66? (a) 72 (b) 7200 (c) 720
  3. 3.√69 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.3 (d) 8.6
  4. 4.Best estimate of 2108 ÷ 23? (a) 105 (b) 1050 (c) 10500
  5. 5.Best estimate of 7563 ÷ 86? (a) 84 (b) 8400 (c) 840
  6. 6.√98 to 1 decimal place? (a) 10.1 (b) 10.0 (c) 9.9 (d) 9.8
  7. 7.√30 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.6 (d) 5.5
  8. 8.√21 to 1 decimal place? (a) 4.4 (b) 4.6 (c) 4.5 (d) 4.3
  9. 9.√90 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.5
  10. 10.Best estimate of 3914 ÷ 76? (a) 4900 (b) 490 (c) 49
  11. 11.√72 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.7 (d) 8.4
  12. 12.Best estimate of 1460 ÷ 36? (a) 3700 (b) 37 (c) 370
  13. 13.Best estimate of 959 ÷ 28? (a) 320 (b) 32 (c) 3200
  14. 14.√47 to 1 decimal place? (a) 7.0 (b) 7.2 (c) 7.1 (d) 6.9
  15. 15.√40 to 1 decimal place? (a) 6.3 (b) 6.6 (c) 6.5 (d) 6.4
  16. 16.√50 to 1 decimal place? (a) 7.3 (b) 7.0 (c) 7.1 (d) 7.2
  17. 17.√35 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 5.7 (d) 5.6
  18. 18.Best estimate of 2060 ÷ 41? (a) 5200 (b) 520 (c) 52
  19. 19.Best estimate of 4461 ÷ 58? (a) 740 (b) 74 (c) 7400
  20. 20.Best estimate of 565 ÷ 24? (a) 28 (b) 2800 (c) 280
  21. 21.Best estimate of 6424 ÷ 84? (a) 8000 (b) 80 (c) 800
  22. 22.√92 to 1 decimal place? (a) 9.9 (b) 9.6 (c) 9.7 (d) 9.8
  23. 23.√37 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 6.2 (d) 5.9
  24. 24.Best estimate of 6697 ÷ 82? (a) 8400 (b) 840 (c) 84
  25. 25.√55 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.5 (d) 7.2
  26. 26.√53 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.4 (d) 7.3
  27. 27.Best estimate of 854 ÷ 46? (a) 1700 (b) 170 (c) 17
  28. 28.√27 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.4 (d) 5.3
  29. 29.√23 to 1 decimal place? (a) 4.7 (b) 4.6 (c) 4.5 (d) 4.8
  30. 30.Best estimate of 1335 ÷ 62? (a) 220 (b) 22 (c) 2200
  31. 31.Best estimate of 1742 ÷ 79? (a) 2200 (b) 22 (c) 220
  32. 32.Best estimate of 2032 ÷ 24? (a) 102 (b) 1020 (c) 10200
  33. 33.Best estimate of 4631 ÷ 59? (a) 7700 (b) 770 (c) 77
  34. 34.Best estimate of 850 ÷ 26? (a) 2800 (b) 28 (c) 280
  35. 35.Best estimate of 3199 ÷ 72? (a) 46 (b) 4600 (c) 460
  36. 36.√32 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.8 (d) 5.5
  37. 37.Best estimate of 1429 ÷ 76? (a) 1800 (b) 180 (c) 18
  38. 38.Best estimate of 1259 ÷ 29? (a) 42 (b) 420 (c) 4200
  39. 39.Best estimate of 4270 ÷ 67? (a) 610 (b) 6100 (c) 61
  40. 40.Best estimate of 819 ÷ 48? (a) 1600 (b) 16 (c) 160

Answer key

  1. 8.8
  2. 72
  3. 8.3
  4. 105
  5. 84
  6. 9.9
  7. 5.5
  8. 4.6
  9. 9.5
  10. 49
  11. 8.5
  12. 37
  13. 32
  14. 6.9
  15. 6.3
  16. 7.1
  17. 5.9
  18. 52
  19. 74
  20. 28
  21. 80
  22. 9.6
  23. 6.1
  24. 84
  25. 7.4
  26. 7.3
  27. 17
  28. 5.2
  29. 4.8
  30. 22
  31. 22
  32. 102
  33. 77
  34. 28
  35. 46
  36. 5.7
  37. 18
  38. 42
  39. 61
  40. 16

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