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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 471 · 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 526 ÷ 26? (a) 180 (b) 1800 (c) 18
  2. 2.√96 to 1 decimal place? (a) 9.7 (b) 9.5 (c) 9.6 (d) 9.8
  3. 3.√42 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.5 (d) 6.7
  4. 4.Best estimate of 4227 ÷ 51? (a) 8500 (b) 850 (c) 85
  5. 5.√50 to 1 decimal place? (a) 7.1 (b) 7.3 (c) 7.0 (d) 7.2
  6. 6.√58 to 1 decimal place? (a) 7.7 (b) 7.5 (c) 7.4 (d) 7.6
  7. 7.√52 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.1 (d) 7.0
  8. 8.√35 to 1 decimal place? (a) 6.0 (b) 5.7 (c) 5.9 (d) 5.8
  9. 9.Best estimate of 3161 ÷ 86? (a) 350 (b) 35 (c) 3500
  10. 10.√48 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 7.0 (d) 6.8
  11. 11.√34 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.7 (d) 5.8
  12. 12.√37 to 1 decimal place? (a) 6.4 (b) 6.2 (c) 6.1 (d) 6.3
  13. 13.Best estimate of 3201 ÷ 51? (a) 6400 (b) 64 (c) 640
  14. 14.Best estimate of 1700 ÷ 46? (a) 3400 (b) 340 (c) 34
  15. 15.Best estimate of 3866 ÷ 77? (a) 48 (b) 4800 (c) 480
  16. 16.Best estimate of 2432 ÷ 42? (a) 610 (b) 6100 (c) 61
  17. 17.Best estimate of 6131 ÷ 86? (a) 6800 (b) 68 (c) 680
  18. 18.Best estimate of 3472 ÷ 66? (a) 500 (b) 50 (c) 5000
  19. 19.Best estimate of 3985 ÷ 54? (a) 800 (b) 8000 (c) 80
  20. 20.Best estimate of 1818 ÷ 33? (a) 610 (b) 6100 (c) 61
  21. 21.Best estimate of 486 ÷ 24? (a) 2400 (b) 24 (c) 240
  22. 22.Best estimate of 3471 ÷ 88? (a) 3900 (b) 39 (c) 390
  23. 23.Best estimate of 4718 ÷ 66? (a) 6700 (b) 670 (c) 67
  24. 24.√69 to 1 decimal place? (a) 8.1 (b) 8.4 (c) 8.2 (d) 8.3
  25. 25.Best estimate of 1826 ÷ 28? (a) 6100 (b) 61 (c) 610
  26. 26.Best estimate of 4925 ÷ 82? (a) 62 (b) 620 (c) 6200
  27. 27.Best estimate of 1031 ÷ 52? (a) 2100 (b) 21 (c) 210
  28. 28.√84 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.1 (d) 9.3
  29. 29.Best estimate of 5192 ÷ 82? (a) 65 (b) 6500 (c) 650
  30. 30.Best estimate of 2544 ÷ 66? (a) 360 (b) 36 (c) 3600
  31. 31.Best estimate of 1231 ÷ 21? (a) 62 (b) 620 (c) 6200
  32. 32.Best estimate of 1210 ÷ 72? (a) 17 (b) 1700 (c) 170
  33. 33.√47 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.0 (d) 6.9
  34. 34.√70 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.5 (d) 8.4
  35. 35.Best estimate of 1538 ÷ 26? (a) 5100 (b) 510 (c) 51
  36. 36.Best estimate of 2432 ÷ 72? (a) 3500 (b) 350 (c) 35
  37. 37.√27 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.4 (d) 5.2
  38. 38.Best estimate of 4759 ÷ 66? (a) 680 (b) 68 (c) 6800
  39. 39.Best estimate of 1154 ÷ 26? (a) 3800 (b) 380 (c) 38
  40. 40.Best estimate of 2874 ÷ 36? (a) 720 (b) 72 (c) 7200

Answer key

  1. 18
  2. 9.8
  3. 6.5
  4. 85
  5. 7.1
  6. 7.6
  7. 7.2
  8. 5.9
  9. 35
  10. 6.9
  11. 5.8
  12. 6.1
  13. 64
  14. 34
  15. 48
  16. 61
  17. 68
  18. 50
  19. 80
  20. 61
  21. 24
  22. 39
  23. 67
  24. 8.3
  25. 61
  26. 62
  27. 21
  28. 9.2
  29. 65
  30. 36
  31. 62
  32. 17
  33. 6.9
  34. 8.4
  35. 51
  36. 35
  37. 5.2
  38. 68
  39. 38
  40. 72

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