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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 748 · 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.√29 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.2 (d) 5.1
  2. 2.√71 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.2 (d) 8.3
  3. 3.√52 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.4 (d) 7.3
  4. 4.Best estimate of 1733 ÷ 44? (a) 430 (b) 4300 (c) 43
  5. 5.Best estimate of 1200 ÷ 58? (a) 20 (b) 2000 (c) 200
  6. 6.√42 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.3 (d) 6.6
  7. 7.√41 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.5 (d) 6.2
  8. 8.Best estimate of 1575 ÷ 86? (a) 180 (b) 1800 (c) 18
  9. 9.Best estimate of 2547 ÷ 62? (a) 420 (b) 4200 (c) 42
  10. 10.√67 to 1 decimal place? (a) 8.3 (b) 8.1 (c) 8.0 (d) 8.2
  11. 11.Best estimate of 722 ÷ 56? (a) 1200 (b) 120 (c) 12
  12. 12.√78 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.8 (d) 8.9
  13. 13.√28 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.6 (d) 5.3
  14. 14.Best estimate of 4287 ÷ 46? (a) 860 (b) 86 (c) 8600
  15. 15.Best estimate of 2241 ÷ 29? (a) 7500 (b) 75 (c) 750
  16. 16.Best estimate of 2311 ÷ 62? (a) 3900 (b) 39 (c) 390
  17. 17.√69 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.2 (d) 8.3
  18. 18.√74 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.8 (d) 8.5
  19. 19.√22 to 1 decimal place? (a) 4.7 (b) 4.5 (c) 4.6 (d) 4.8
  20. 20.Best estimate of 2577 ÷ 89? (a) 290 (b) 29 (c) 2900
  21. 21.√90 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.6 (d) 9.4
  22. 22.√24 to 1 decimal place? (a) 4.9 (b) 5.1 (c) 5.2 (d) 5.0
  23. 23.Best estimate of 2875 ÷ 37? (a) 72 (b) 7200 (c) 720
  24. 24.√21 to 1 decimal place? (a) 4.5 (b) 4.7 (c) 4.6 (d) 4.4
  25. 25.Best estimate of 1121 ÷ 49? (a) 2200 (b) 220 (c) 22
  26. 26.Best estimate of 1710 ÷ 38? (a) 430 (b) 43 (c) 4300
  27. 27.Best estimate of 1401 ÷ 52? (a) 280 (b) 2800 (c) 28
  28. 28.√47 to 1 decimal place? (a) 7.1 (b) 7.0 (c) 6.9 (d) 7.2
  29. 29.√65 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.3 (d) 8.2
  30. 30.√53 to 1 decimal place? (a) 7.3 (b) 7.5 (c) 7.4 (d) 7.6
  31. 31.√94 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.9 (d) 9.7
  32. 32.Best estimate of 889 ÷ 49? (a) 1800 (b) 18 (c) 180
  33. 33.√86 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.2 (d) 9.4
  34. 34.Best estimate of 1568 ÷ 32? (a) 52 (b) 5200 (c) 520
  35. 35.Best estimate of 2991 ÷ 76? (a) 3700 (b) 37 (c) 370
  36. 36.Best estimate of 2167 ÷ 72? (a) 3100 (b) 31 (c) 310
  37. 37.Best estimate of 1290 ÷ 57? (a) 220 (b) 2200 (c) 22
  38. 38.Best estimate of 3512 ÷ 52? (a) 700 (b) 7000 (c) 70
  39. 39.Best estimate of 2772 ÷ 88? (a) 31 (b) 3100 (c) 310
  40. 40.Best estimate of 1205 ÷ 72? (a) 17 (b) 1700 (c) 170

Answer key

  1. 5.4
  2. 8.4
  3. 7.2
  4. 43
  5. 20
  6. 6.5
  7. 6.4
  8. 18
  9. 42
  10. 8.2
  11. 12
  12. 8.8
  13. 5.3
  14. 86
  15. 75
  16. 39
  17. 8.3
  18. 8.6
  19. 4.7
  20. 29
  21. 9.5
  22. 4.9
  23. 72
  24. 4.6
  25. 22
  26. 43
  27. 28
  28. 6.9
  29. 8.1
  30. 7.3
  31. 9.7
  32. 18
  33. 9.3
  34. 52
  35. 37
  36. 31
  37. 22
  38. 70
  39. 31
  40. 17

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