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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 693 · 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.√96 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.8 (d) 9.7
  2. 2.√41 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  3. 3.√98 to 1 decimal place? (a) 10.2 (b) 10.0 (c) 9.9 (d) 10.1
  4. 4.√65 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 7.8 (d) 8.0
  5. 5.Best estimate of 1905 ÷ 64? (a) 3200 (b) 320 (c) 32
  6. 6.Best estimate of 3800 ÷ 68? (a) 5400 (b) 54 (c) 540
  7. 7.√40 to 1 decimal place? (a) 6.3 (b) 6.6 (c) 6.5 (d) 6.4
  8. 8.Best estimate of 844 ÷ 56? (a) 1400 (b) 14 (c) 140
  9. 9.√31 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.6 (d) 5.4
  10. 10.Best estimate of 501 ÷ 27? (a) 17 (b) 1700 (c) 170
  11. 11.√32 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 5.7 (d) 5.8
  12. 12.Best estimate of 5556 ÷ 58? (a) 93 (b) 930 (c) 9300
  13. 13.Best estimate of 4242 ÷ 76? (a) 5300 (b) 530 (c) 53
  14. 14.√22 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 4.7 (d) 4.6
  15. 15.Best estimate of 496 ÷ 22? (a) 2500 (b) 250 (c) 25
  16. 16.Best estimate of 1675 ÷ 37? (a) 420 (b) 42 (c) 4200
  17. 17.√74 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.3 (d) 8.6
  18. 18.Best estimate of 2434 ÷ 36? (a) 61 (b) 610 (c) 6100
  19. 19.√82 to 1 decimal place? (a) 9.0 (b) 9.3 (c) 9.1 (d) 9.2
  20. 20.√46 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.7 (d) 6.9
  21. 21.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 8.0
  22. 22.√71 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.5 (d) 8.2
  23. 23.Best estimate of 3264 ÷ 57? (a) 540 (b) 5400 (c) 54
  24. 24.Best estimate of 1062 ÷ 44? (a) 27 (b) 270 (c) 2700
  25. 25.√58 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.8 (d) 7.6
  26. 26.Best estimate of 2418 ÷ 36? (a) 6000 (b) 600 (c) 60
  27. 27.Best estimate of 5332 ÷ 72? (a) 760 (b) 76 (c) 7600
  28. 28.Best estimate of 3818 ÷ 46? (a) 760 (b) 76 (c) 7600
  29. 29.√59 to 1 decimal place? (a) 7.8 (b) 7.6 (c) 7.5 (d) 7.7
  30. 30.Best estimate of 4765 ÷ 66? (a) 6800 (b) 680 (c) 68
  31. 31.Best estimate of 2637 ÷ 78? (a) 330 (b) 3300 (c) 33
  32. 32.Best estimate of 2335 ÷ 38? (a) 58 (b) 5800 (c) 580
  33. 33.√55 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.3 (d) 7.6
  34. 34.Best estimate of 1848 ÷ 53? (a) 370 (b) 3700 (c) 37
  35. 35.Best estimate of 5352 ÷ 84? (a) 67 (b) 670 (c) 6700
  36. 36.√92 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.4 (d) 9.6
  37. 37.Best estimate of 6165 ÷ 69? (a) 880 (b) 8800 (c) 88
  38. 38.Best estimate of 4003 ÷ 76? (a) 5000 (b) 50 (c) 500
  39. 39.Best estimate of 4143 ÷ 69? (a) 59 (b) 5900 (c) 590
  40. 40.Best estimate of 4156 ÷ 56? (a) 6900 (b) 690 (c) 69

Answer key

  1. 9.8
  2. 6.4
  3. 9.9
  4. 8.1
  5. 32
  6. 54
  7. 6.3
  8. 14
  9. 5.6
  10. 17
  11. 5.7
  12. 93
  13. 53
  14. 4.7
  15. 25
  16. 42
  17. 8.6
  18. 61
  19. 9.1
  20. 6.8
  21. 7.8
  22. 8.4
  23. 54
  24. 27
  25. 7.6
  26. 60
  27. 76
  28. 76
  29. 7.7
  30. 68
  31. 33
  32. 58
  33. 7.4
  34. 37
  35. 67
  36. 9.6
  37. 88
  38. 50
  39. 59
  40. 69

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