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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 5 · 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 3260 ÷ 82? (a) 4100 (b) 41 (c) 410
  2. 2.Best estimate of 2478 ÷ 47? (a) 5000 (b) 500 (c) 50
  3. 3.√59 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.4 (d) 7.5
  4. 4.Best estimate of 3856 ÷ 62? (a) 64 (b) 6400 (c) 640
  5. 5.Best estimate of 2583 ÷ 32? (a) 86 (b) 860 (c) 8600
  6. 6.√69 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 8.2 (d) 8.3
  7. 7.Best estimate of 1525 ÷ 86? (a) 170 (b) 17 (c) 1700
  8. 8.Best estimate of 2201 ÷ 24? (a) 1100 (b) 11000 (c) 110
  9. 9.√24 to 1 decimal place? (a) 5.0 (b) 5.1 (c) 5.2 (d) 4.9
  10. 10.√94 to 1 decimal place? (a) 9.9 (b) 9.6 (c) 9.8 (d) 9.7
  11. 11.√71 to 1 decimal place? (a) 8.5 (b) 8.3 (c) 8.6 (d) 8.4
  12. 12.Best estimate of 355 ÷ 27? (a) 120 (b) 12 (c) 1200
  13. 13.√56 to 1 decimal place? (a) 7.7 (b) 7.5 (c) 7.6 (d) 7.8
  14. 14.Best estimate of 6881 ÷ 74? (a) 98 (b) 980 (c) 9800
  15. 15.Best estimate of 524 ÷ 38? (a) 130 (b) 1300 (c) 13
  16. 16.√85 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.0
  17. 17.√32 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.9 (d) 6.0
  18. 18.√61 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.0 (d) 7.8
  19. 19.Best estimate of 569 ÷ 37? (a) 14 (b) 140 (c) 1400
  20. 20.Best estimate of 3494 ÷ 39? (a) 8700 (b) 870 (c) 87
  21. 21.√37 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.4 (d) 6.2
  22. 22.√89 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.4 (d) 9.6
  23. 23.√20 to 1 decimal place? (a) 4.5 (b) 4.8 (c) 4.6 (d) 4.7
  24. 24.Best estimate of 2286 ÷ 62? (a) 380 (b) 38 (c) 3800
  25. 25.√79 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.9 (d) 9.2
  26. 26.Best estimate of 3997 ÷ 56? (a) 67 (b) 670 (c) 6700
  27. 27.Best estimate of 2189 ÷ 38? (a) 5500 (b) 55 (c) 550
  28. 28.Best estimate of 4859 ÷ 53? (a) 9700 (b) 970 (c) 97
  29. 29.Best estimate of 2040 ÷ 71? (a) 2900 (b) 29 (c) 290
  30. 30.Best estimate of 478 ÷ 24? (a) 24 (b) 240 (c) 2400
  31. 31.Best estimate of 3977 ÷ 62? (a) 6600 (b) 66 (c) 660
  32. 32.Best estimate of 1904 ÷ 52? (a) 38 (b) 380 (c) 3800
  33. 33.Best estimate of 697 ÷ 57? (a) 12 (b) 1200 (c) 120
  34. 34.Best estimate of 3008 ÷ 33? (a) 1000 (b) 10000 (c) 100
  35. 35.Best estimate of 1521 ÷ 32? (a) 5100 (b) 51 (c) 510
  36. 36.Best estimate of 2092 ÷ 28? (a) 700 (b) 7000 (c) 70
  37. 37.√40 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.1 (d) 6.2
  38. 38.√45 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.7 (d) 6.5
  39. 39.Best estimate of 5065 ÷ 64? (a) 84 (b) 840 (c) 8400
  40. 40.Best estimate of 3324 ÷ 58? (a) 550 (b) 5500 (c) 55

Answer key

  1. 41
  2. 50
  3. 7.7
  4. 64
  5. 86
  6. 8.3
  7. 17
  8. 110
  9. 4.9
  10. 9.7
  11. 8.4
  12. 12
  13. 7.5
  14. 98
  15. 13
  16. 9.2
  17. 5.7
  18. 7.8
  19. 14
  20. 87
  21. 6.1
  22. 9.4
  23. 4.5
  24. 38
  25. 8.9
  26. 67
  27. 55
  28. 97
  29. 29
  30. 24
  31. 66
  32. 38
  33. 12
  34. 100
  35. 51
  36. 70
  37. 6.3
  38. 6.7
  39. 84
  40. 55

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