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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 159 · 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.√67 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.3 (d) 8.0
  2. 2.Best estimate of 4133 ÷ 87? (a) 460 (b) 46 (c) 4600
  3. 3.Best estimate of 1154 ÷ 69? (a) 1600 (b) 160 (c) 16
  4. 4.Best estimate of 4454 ÷ 64? (a) 7400 (b) 740 (c) 74
  5. 5.Best estimate of 4319 ÷ 51? (a) 860 (b) 86 (c) 8600
  6. 6.√26 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 5.2 (d) 5.3
  7. 7.Best estimate of 2228 ÷ 86? (a) 25 (b) 250 (c) 2500
  8. 8.Best estimate of 3394 ÷ 72? (a) 4800 (b) 48 (c) 480
  9. 9.Best estimate of 3041 ÷ 36? (a) 7600 (b) 76 (c) 760
  10. 10.Best estimate of 4381 ÷ 57? (a) 7300 (b) 730 (c) 73
  11. 11.Best estimate of 2209 ÷ 31? (a) 74 (b) 7400 (c) 740
  12. 12.Best estimate of 3107 ÷ 42? (a) 78 (b) 780 (c) 7800
  13. 13.Best estimate of 3583 ÷ 42? (a) 90 (b) 900 (c) 9000
  14. 14.Best estimate of 2619 ÷ 58? (a) 4400 (b) 440 (c) 44
  15. 15.√79 to 1 decimal place? (a) 8.9 (b) 8.7 (c) 9.0 (d) 8.8
  16. 16.√98 to 1 decimal place? (a) 10.1 (b) 10.2 (c) 10.0 (d) 9.9
  17. 17.Best estimate of 4215 ÷ 67? (a) 6000 (b) 600 (c) 60
  18. 18.Best estimate of 2182 ÷ 57? (a) 36 (b) 360 (c) 3600
  19. 19.Best estimate of 4542 ÷ 49? (a) 91 (b) 910 (c) 9100
  20. 20.√37 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.4 (d) 6.3
  21. 21.√85 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.0 (d) 9.2
  22. 22.√29 to 1 decimal place? (a) 5.6 (b) 5.4 (c) 5.3 (d) 5.5
  23. 23.√43 to 1 decimal place? (a) 6.5 (b) 6.7 (c) 6.8 (d) 6.6
  24. 24.Best estimate of 2071 ÷ 74? (a) 30 (b) 300 (c) 3000
  25. 25.√35 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 6.2 (d) 5.9
  26. 26.Best estimate of 1122 ÷ 59? (a) 19 (b) 190 (c) 1900
  27. 27.√44 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.5 (d) 6.7
  28. 28.Best estimate of 4447 ÷ 57? (a) 740 (b) 7400 (c) 74
  29. 29.Best estimate of 3693 ÷ 51? (a) 740 (b) 7400 (c) 74
  30. 30.√48 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.7 (d) 6.9
  31. 31.√92 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.3 (d) 9.5
  32. 32.√22 to 1 decimal place? (a) 4.5 (b) 4.7 (c) 4.6 (d) 4.4
  33. 33.Best estimate of 1488 ÷ 34? (a) 50 (b) 5000 (c) 500
  34. 34.Best estimate of 5244 ÷ 66? (a) 75 (b) 7500 (c) 750
  35. 35.Best estimate of 551 ÷ 34? (a) 1800 (b) 180 (c) 18
  36. 36.√71 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.7 (d) 8.6
  37. 37.√90 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.3 (d) 9.5
  38. 38.√77 to 1 decimal place? (a) 8.8 (b) 9.0 (c) 9.1 (d) 8.9
  39. 39.√20 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 4.6 (d) 4.5
  40. 40.√56 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.8 (d) 7.7

Answer key

  1. 8.2
  2. 46
  3. 16
  4. 74
  5. 86
  6. 5.1
  7. 25
  8. 48
  9. 76
  10. 73
  11. 74
  12. 78
  13. 90
  14. 44
  15. 8.9
  16. 9.9
  17. 60
  18. 36
  19. 91
  20. 6.1
  21. 9.2
  22. 5.4
  23. 6.6
  24. 30
  25. 5.9
  26. 19
  27. 6.6
  28. 74
  29. 74
  30. 6.9
  31. 9.6
  32. 4.7
  33. 50
  34. 75
  35. 18
  36. 8.4
  37. 9.5
  38. 8.8
  39. 4.5
  40. 7.5

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