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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 274 · 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.Best estimate of 2830 ÷ 82? (a) 35 (b) 350 (c) 3500
  2. 2.Best estimate of 2629 ÷ 87? (a) 2900 (b) 29 (c) 290
  3. 3.Best estimate of 1829 ÷ 21? (a) 910 (b) 9100 (c) 91
  4. 4.Best estimate of 2849 ÷ 48? (a) 5700 (b) 57 (c) 570
  5. 5.Best estimate of 3953 ÷ 61? (a) 6600 (b) 660 (c) 66
  6. 6.√83 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.1 (d) 9.4
  7. 7.Best estimate of 1047 ÷ 72? (a) 150 (b) 1500 (c) 15
  8. 8.Best estimate of 5654 ÷ 64? (a) 940 (b) 94 (c) 9400
  9. 9.Best estimate of 1331 ÷ 24? (a) 670 (b) 6700 (c) 67
  10. 10.Best estimate of 381 ÷ 27? (a) 130 (b) 1300 (c) 13
  11. 11.Best estimate of 2429 ÷ 39? (a) 610 (b) 61 (c) 6100
  12. 12.Best estimate of 2110 ÷ 46? (a) 420 (b) 4200 (c) 42
  13. 13.√42 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  14. 14.Best estimate of 3550 ÷ 69? (a) 510 (b) 5100 (c) 51
  15. 15.√34 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 6.0 (d) 5.9
  16. 16.√84 to 1 decimal place? (a) 9.0 (b) 9.3 (c) 9.2 (d) 9.1
  17. 17.Best estimate of 856 ÷ 47? (a) 170 (b) 17 (c) 1700
  18. 18.√44 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.6 (d) 6.3
  19. 19.√53 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.1 (d) 7.2
  20. 20.Best estimate of 877 ÷ 24? (a) 440 (b) 44 (c) 4400
  21. 21.√92 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.6 (d) 9.7
  22. 22.Best estimate of 1479 ÷ 29? (a) 49 (b) 490 (c) 4900
  23. 23.√66 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.4 (d) 8.1
  24. 24.Best estimate of 4020 ÷ 68? (a) 570 (b) 5700 (c) 57
  25. 25.√47 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 7.2 (d) 7.1
  26. 26.Best estimate of 3078 ÷ 86? (a) 34 (b) 3400 (c) 340
  27. 27.Best estimate of 1064 ÷ 33? (a) 3500 (b) 35 (c) 350
  28. 28.Best estimate of 471 ÷ 32? (a) 16 (b) 1600 (c) 160
  29. 29.Best estimate of 452 ÷ 33? (a) 150 (b) 1500 (c) 15
  30. 30.Best estimate of 1903 ÷ 71? (a) 27 (b) 270 (c) 2700
  31. 31.√35 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 6.0 (d) 5.8
  32. 32.Best estimate of 3081 ÷ 39? (a) 770 (b) 7700 (c) 77
  33. 33.Best estimate of 1893 ÷ 73? (a) 27 (b) 270 (c) 2700
  34. 34.√30 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.4 (d) 5.3
  35. 35.Best estimate of 3345 ÷ 88? (a) 3700 (b) 37 (c) 370
  36. 36.Best estimate of 1888 ÷ 66? (a) 270 (b) 27 (c) 2700
  37. 37.Best estimate of 987 ÷ 29? (a) 3300 (b) 33 (c) 330
  38. 38.Best estimate of 537 ÷ 36? (a) 130 (b) 1300 (c) 13
  39. 39.√71 to 1 decimal place? (a) 8.5 (b) 8.7 (c) 8.4 (d) 8.6
  40. 40.Best estimate of 1488 ÷ 21? (a) 740 (b) 7400 (c) 74

Answer key

  1. 35
  2. 29
  3. 91
  4. 57
  5. 66
  6. 9.1
  7. 15
  8. 94
  9. 67
  10. 13
  11. 61
  12. 42
  13. 6.5
  14. 51
  15. 5.8
  16. 9.2
  17. 17
  18. 6.6
  19. 7.3
  20. 44
  21. 9.6
  22. 49
  23. 8.1
  24. 57
  25. 6.9
  26. 34
  27. 35
  28. 16
  29. 15
  30. 27
  31. 5.9
  32. 77
  33. 27
  34. 5.5
  35. 37
  36. 27
  37. 33
  38. 13
  39. 8.4
  40. 74

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