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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 731 · 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 2433 ÷ 51? (a) 4900 (b) 49 (c) 490
  2. 2.√59 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.4 (d) 7.7
  3. 3.Best estimate of 1680 ÷ 46? (a) 340 (b) 34 (c) 3400
  4. 4.√40 to 1 decimal place? (a) 6.4 (b) 6.1 (c) 6.3 (d) 6.2
  5. 5.Best estimate of 3912 ÷ 73? (a) 560 (b) 56 (c) 5600
  6. 6.Best estimate of 884 ÷ 59? (a) 150 (b) 15 (c) 1500
  7. 7.Best estimate of 4562 ÷ 54? (a) 910 (b) 91 (c) 9100
  8. 8.Best estimate of 4395 ÷ 86? (a) 4900 (b) 490 (c) 49
  9. 9.Best estimate of 6145 ÷ 78? (a) 7700 (b) 770 (c) 77
  10. 10.√20 to 1 decimal place? (a) 4.6 (b) 4.5 (c) 4.4 (d) 4.7
  11. 11.Best estimate of 1822 ÷ 69? (a) 26 (b) 260 (c) 2600
  12. 12.Best estimate of 971 ÷ 46? (a) 1900 (b) 19 (c) 190
  13. 13.Best estimate of 2718 ÷ 68? (a) 39 (b) 3900 (c) 390
  14. 14.√23 to 1 decimal place? (a) 4.5 (b) 4.6 (c) 4.8 (d) 4.7
  15. 15.√51 to 1 decimal place? (a) 7.3 (b) 7.2 (c) 7.1 (d) 7.4
  16. 16.Best estimate of 2788 ÷ 33? (a) 930 (b) 93 (c) 9300
  17. 17.Best estimate of 6881 ÷ 84? (a) 86 (b) 8600 (c) 860
  18. 18.Best estimate of 1673 ÷ 41? (a) 4200 (b) 42 (c) 420
  19. 19.Best estimate of 3646 ÷ 57? (a) 610 (b) 61 (c) 6100
  20. 20.√84 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.3 (d) 9.2
  21. 21.Best estimate of 4813 ÷ 53? (a) 96 (b) 960 (c) 9600
  22. 22.Best estimate of 1147 ÷ 42? (a) 2900 (b) 29 (c) 290
  23. 23.√78 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.8 (d) 8.6
  24. 24.Best estimate of 5659 ÷ 84? (a) 71 (b) 710 (c) 7100
  25. 25.√43 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.3
  26. 26.√37 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 5.9 (d) 6.1
  27. 27.Best estimate of 3663 ÷ 77? (a) 460 (b) 4600 (c) 46
  28. 28.Best estimate of 4395 ÷ 63? (a) 730 (b) 73 (c) 7300
  29. 29.Best estimate of 1637 ÷ 53? (a) 3300 (b) 330 (c) 33
  30. 30.√41 to 1 decimal place? (a) 6.4 (b) 6.7 (c) 6.5 (d) 6.6
  31. 31.√21 to 1 decimal place? (a) 4.9 (b) 4.7 (c) 4.6 (d) 4.8
  32. 32.√35 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 6.1 (d) 5.9
  33. 33.√26 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.4 (d) 5.2
  34. 34.√98 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.7 (d) 9.6
  35. 35.Best estimate of 1996 ÷ 39? (a) 5000 (b) 500 (c) 50
  36. 36.√28 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.2 (d) 5.5
  37. 37.Best estimate of 1573 ÷ 31? (a) 5200 (b) 520 (c) 52
  38. 38.√34 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 5.7 (d) 5.9
  39. 39.Best estimate of 2224 ÷ 32? (a) 74 (b) 740 (c) 7400
  40. 40.√74 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.6 (d) 8.5

Answer key

  1. 49
  2. 7.7
  3. 34
  4. 6.3
  5. 56
  6. 15
  7. 91
  8. 49
  9. 77
  10. 4.5
  11. 26
  12. 19
  13. 39
  14. 4.8
  15. 7.1
  16. 93
  17. 86
  18. 42
  19. 61
  20. 9.2
  21. 96
  22. 29
  23. 8.8
  24. 71
  25. 6.6
  26. 6.1
  27. 46
  28. 73
  29. 33
  30. 6.4
  31. 4.6
  32. 5.9
  33. 5.1
  34. 9.9
  35. 50
  36. 5.3
  37. 52
  38. 5.8
  39. 74
  40. 8.6

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