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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 518 · 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 1496 ÷ 61? (a) 250 (b) 2500 (c) 25
  2. 2.√98 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.8 (d) 10.1
  3. 3.Best estimate of 4185 ÷ 72? (a) 6000 (b) 60 (c) 600
  4. 4.Best estimate of 869 ÷ 32? (a) 2900 (b) 290 (c) 29
  5. 5.Best estimate of 5378 ÷ 78? (a) 670 (b) 6700 (c) 67
  6. 6.Best estimate of 309 ÷ 23? (a) 15 (b) 150 (c) 1500
  7. 7.Best estimate of 5988 ÷ 76? (a) 75 (b) 750 (c) 7500
  8. 8.Best estimate of 746 ÷ 39? (a) 190 (b) 19 (c) 1900
  9. 9.Best estimate of 1489 ÷ 29? (a) 500 (b) 50 (c) 5000
  10. 10.√22 to 1 decimal place? (a) 4.6 (b) 4.7 (c) 4.8 (d) 4.9
  11. 11.√28 to 1 decimal place? (a) 5.5 (b) 5.2 (c) 5.4 (d) 5.3
  12. 12.Best estimate of 2751 ÷ 32? (a) 9200 (b) 92 (c) 920
  13. 13.√34 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.6 (d) 5.8
  14. 14.Best estimate of 2278 ÷ 86? (a) 250 (b) 2500 (c) 25
  15. 15.Best estimate of 1670 ÷ 32? (a) 560 (b) 5600 (c) 56
  16. 16.Best estimate of 1948 ÷ 31? (a) 650 (b) 65 (c) 6500
  17. 17.√82 to 1 decimal place? (a) 9.3 (b) 9.0 (c) 9.2 (d) 9.1
  18. 18.√94 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.7 (d) 9.5
  19. 19.√23 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 4.8 (d) 4.9
  20. 20.√92 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.4
  21. 21.Best estimate of 415 ÷ 27? (a) 140 (b) 14 (c) 1400
  22. 22.√47 to 1 decimal place? (a) 7.1 (b) 7.0 (c) 6.8 (d) 6.9
  23. 23.Best estimate of 4023 ÷ 43? (a) 101 (b) 10100 (c) 1010
  24. 24.√66 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.2 (d) 8.0
  25. 25.√71 to 1 decimal place? (a) 8.5 (b) 8.3 (c) 8.4 (d) 8.2
  26. 26.Best estimate of 3870 ÷ 53? (a) 7700 (b) 77 (c) 770
  27. 27.√86 to 1 decimal place? (a) 9.4 (b) 9.1 (c) 9.2 (d) 9.3
  28. 28.√76 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.8 (d) 8.5
  29. 29.Best estimate of 2766 ÷ 89? (a) 31 (b) 310 (c) 3100
  30. 30.Best estimate of 2380 ÷ 58? (a) 4000 (b) 40 (c) 400
  31. 31.Best estimate of 1333 ÷ 52? (a) 27 (b) 2700 (c) 270
  32. 32.Best estimate of 771 ÷ 41? (a) 190 (b) 1900 (c) 19
  33. 33.√27 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.0 (d) 5.3
  34. 34.Best estimate of 2523 ÷ 52? (a) 5000 (b) 500 (c) 50
  35. 35.√51 to 1 decimal place? (a) 7.2 (b) 7.0 (c) 6.9 (d) 7.1
  36. 36.Best estimate of 2880 ÷ 68? (a) 41 (b) 4100 (c) 410
  37. 37.Best estimate of 2773 ÷ 78? (a) 350 (b) 3500 (c) 35
  38. 38.√80 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.6 (d) 8.9
  39. 39.Best estimate of 1214 ÷ 52? (a) 2400 (b) 240 (c) 24
  40. 40.Best estimate of 2103 ÷ 29? (a) 70 (b) 7000 (c) 700

Answer key

  1. 25
  2. 9.9
  3. 60
  4. 29
  5. 67
  6. 15
  7. 75
  8. 19
  9. 50
  10. 4.7
  11. 5.3
  12. 92
  13. 5.8
  14. 25
  15. 56
  16. 65
  17. 9.1
  18. 9.7
  19. 4.8
  20. 9.6
  21. 14
  22. 6.9
  23. 101
  24. 8.1
  25. 8.4
  26. 77
  27. 9.3
  28. 8.7
  29. 31
  30. 40
  31. 27
  32. 19
  33. 5.2
  34. 50
  35. 7.1
  36. 41
  37. 35
  38. 8.9
  39. 24
  40. 70

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