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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 534 · 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 4933 ÷ 53? (a) 9900 (b) 99 (c) 990
  2. 2.Best estimate of 1192 ÷ 37? (a) 300 (b) 3000 (c) 30
  3. 3.Best estimate of 2437 ÷ 56? (a) 4100 (b) 410 (c) 41
  4. 4.Best estimate of 393 ÷ 32? (a) 130 (b) 1300 (c) 13
  5. 5.√82 to 1 decimal place? (a) 8.9 (b) 9.1 (c) 9.0 (d) 9.2
  6. 6.√43 to 1 decimal place? (a) 6.8 (b) 6.5 (c) 6.6 (d) 6.7
  7. 7.√85 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.1
  8. 8.Best estimate of 6071 ÷ 72? (a) 870 (b) 87 (c) 8700
  9. 9.Best estimate of 2729 ÷ 87? (a) 300 (b) 3000 (c) 30
  10. 10.√61 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.8
  11. 11.√75 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 9.0
  12. 12.Best estimate of 2761 ÷ 41? (a) 6900 (b) 690 (c) 69
  13. 13.Best estimate of 1458 ÷ 27? (a) 4900 (b) 490 (c) 49
  14. 14.√38 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 5.9 (d) 6.0
  15. 15.Best estimate of 6832 ÷ 82? (a) 850 (b) 85 (c) 8500
  16. 16.√88 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.3 (d) 9.5
  17. 17.√40 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.5 (d) 6.3
  18. 18.Best estimate of 1782 ÷ 34? (a) 5900 (b) 590 (c) 59
  19. 19.Best estimate of 1075 ÷ 46? (a) 22 (b) 2200 (c) 220
  20. 20.Best estimate of 1794 ÷ 61? (a) 300 (b) 30 (c) 3000
  21. 21.√20 to 1 decimal place? (a) 4.3 (b) 4.4 (c) 4.5 (d) 4.6
  22. 22.√37 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.0 (d) 6.1
  23. 23.Best estimate of 2150 ÷ 57? (a) 3600 (b) 36 (c) 360
  24. 24.√27 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.2 (d) 5.1
  25. 25.√98 to 1 decimal place? (a) 9.6 (b) 9.9 (c) 9.7 (d) 9.8
  26. 26.Best estimate of 3719 ÷ 61? (a) 62 (b) 6200 (c) 620
  27. 27.√55 to 1 decimal place? (a) 7.5 (b) 7.2 (c) 7.4 (d) 7.3
  28. 28.√78 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 9.0
  29. 29.Best estimate of 2249 ÷ 76? (a) 280 (b) 2800 (c) 28
  30. 30.Best estimate of 5796 ÷ 76? (a) 720 (b) 7200 (c) 72
  31. 31.Best estimate of 2106 ÷ 23? (a) 1050 (b) 105 (c) 10500
  32. 32.Best estimate of 2159 ÷ 63? (a) 36 (b) 3600 (c) 360
  33. 33.Best estimate of 1382 ÷ 89? (a) 150 (b) 15 (c) 1500
  34. 34.√24 to 1 decimal place? (a) 5.1 (b) 4.9 (c) 5.0 (d) 4.8
  35. 35.Best estimate of 6204 ÷ 69? (a) 89 (b) 890 (c) 8900
  36. 36.Best estimate of 973 ÷ 44? (a) 240 (b) 2400 (c) 24
  37. 37.Best estimate of 2991 ÷ 36? (a) 7500 (b) 750 (c) 75
  38. 38.Best estimate of 5480 ÷ 76? (a) 690 (b) 69 (c) 6900
  39. 39.Best estimate of 4894 ÷ 71? (a) 70 (b) 7000 (c) 700
  40. 40.√46 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.5 (d) 6.8

Answer key

  1. 99
  2. 30
  3. 41
  4. 13
  5. 9.1
  6. 6.6
  7. 9.2
  8. 87
  9. 30
  10. 7.8
  11. 8.7
  12. 69
  13. 49
  14. 6.2
  15. 85
  16. 9.4
  17. 6.3
  18. 59
  19. 22
  20. 30
  21. 4.5
  22. 6.1
  23. 36
  24. 5.2
  25. 9.9
  26. 62
  27. 7.4
  28. 8.8
  29. 28
  30. 72
  31. 105
  32. 36
  33. 15
  34. 4.9
  35. 89
  36. 24
  37. 75
  38. 69
  39. 70
  40. 6.8

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