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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 831 · 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 2869 ÷ 33? (a) 960 (b) 96 (c) 9600
  2. 2.Best estimate of 2942 ÷ 52? (a) 590 (b) 59 (c) 5900
  3. 3.Best estimate of 1693 ÷ 66? (a) 2400 (b) 24 (c) 240
  4. 4.Best estimate of 2157 ÷ 62? (a) 3600 (b) 36 (c) 360
  5. 5.Best estimate of 940 ÷ 62? (a) 16 (b) 1600 (c) 160
  6. 6.Best estimate of 4269 ÷ 49? (a) 850 (b) 85 (c) 8500
  7. 7.Best estimate of 732 ÷ 28? (a) 24 (b) 2400 (c) 240
  8. 8.√92 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 9.7 (d) 9.6
  9. 9.√59 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.6 (d) 7.5
  10. 10.Best estimate of 4333 ÷ 67? (a) 620 (b) 62 (c) 6200
  11. 11.√22 to 1 decimal place? (a) 4.6 (b) 4.8 (c) 4.9 (d) 4.7
  12. 12.Best estimate of 2060 ÷ 59? (a) 34 (b) 3400 (c) 340
  13. 13.Best estimate of 2706 ÷ 46? (a) 540 (b) 54 (c) 5400
  14. 14.Best estimate of 589 ÷ 24? (a) 2900 (b) 290 (c) 29
  15. 15.Best estimate of 903 ÷ 36? (a) 230 (b) 2300 (c) 23
  16. 16.Best estimate of 615 ÷ 24? (a) 3100 (b) 31 (c) 310
  17. 17.Best estimate of 2398 ÷ 71? (a) 34 (b) 3400 (c) 340
  18. 18.Best estimate of 3380 ÷ 62? (a) 560 (b) 5600 (c) 56
  19. 19.√87 to 1 decimal place? (a) 9.3 (b) 9.0 (c) 9.1 (d) 9.2
  20. 20.Best estimate of 2696 ÷ 42? (a) 670 (b) 6700 (c) 67
  21. 21.Best estimate of 5500 ÷ 79? (a) 69 (b) 690 (c) 6900
  22. 22.Best estimate of 729 ÷ 36? (a) 18 (b) 180 (c) 1800
  23. 23.Best estimate of 6069 ÷ 74? (a) 8700 (b) 87 (c) 870
  24. 24.Best estimate of 752 ÷ 52? (a) 1500 (b) 15 (c) 150
  25. 25.√34 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 5.6 (d) 5.8
  26. 26.√55 to 1 decimal place? (a) 7.5 (b) 7.3 (c) 7.2 (d) 7.4
  27. 27.√51 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.1 (d) 7.0
  28. 28.√62 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.0 (d) 7.9
  29. 29.Best estimate of 5239 ÷ 72? (a) 750 (b) 7500 (c) 75
  30. 30.Best estimate of 1321 ÷ 47? (a) 26 (b) 260 (c) 2600
  31. 31.√82 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.0 (d) 8.9
  32. 32.Best estimate of 1705 ÷ 41? (a) 4300 (b) 430 (c) 43
  33. 33.Best estimate of 2614 ÷ 46? (a) 5200 (b) 520 (c) 52
  34. 34.Best estimate of 749 ÷ 26? (a) 2500 (b) 250 (c) 25
  35. 35.√44 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.4 (d) 6.5
  36. 36.√67 to 1 decimal place? (a) 8.3 (b) 8.1 (c) 8.0 (d) 8.2
  37. 37.√98 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 9.8 (d) 9.6
  38. 38.Best estimate of 880 ÷ 59? (a) 15 (b) 1500 (c) 150
  39. 39.Best estimate of 2895 ÷ 32? (a) 9700 (b) 970 (c) 97
  40. 40.Best estimate of 1156 ÷ 36? (a) 2900 (b) 290 (c) 29

Answer key

  1. 96
  2. 59
  3. 24
  4. 36
  5. 16
  6. 85
  7. 24
  8. 9.6
  9. 7.7
  10. 62
  11. 4.7
  12. 34
  13. 54
  14. 29
  15. 23
  16. 31
  17. 34
  18. 56
  19. 9.3
  20. 67
  21. 69
  22. 18
  23. 87
  24. 15
  25. 5.8
  26. 7.4
  27. 7.1
  28. 7.9
  29. 75
  30. 26
  31. 9.1
  32. 43
  33. 52
  34. 25
  35. 6.6
  36. 8.2
  37. 9.9
  38. 15
  39. 97
  40. 29

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