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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 104 · 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.√28 to 1 decimal place? (a) 5.3 (b) 5.0 (c) 5.2 (d) 5.1
  2. 2.Best estimate of 1887 ÷ 41? (a) 47 (b) 4700 (c) 470
  3. 3.√41 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.7
  4. 4.√92 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.4 (d) 9.6
  5. 5.Best estimate of 1190 ÷ 23? (a) 6000 (b) 600 (c) 60
  6. 6.Best estimate of 1230 ÷ 56? (a) 21 (b) 2100 (c) 210
  7. 7.Best estimate of 4635 ÷ 72? (a) 6600 (b) 66 (c) 660
  8. 8.√55 to 1 decimal place? (a) 7.3 (b) 7.2 (c) 7.1 (d) 7.4
  9. 9.Best estimate of 4883 ÷ 72? (a) 7000 (b) 70 (c) 700
  10. 10.Best estimate of 984 ÷ 26? (a) 3300 (b) 330 (c) 33
  11. 11.√24 to 1 decimal place? (a) 5.1 (b) 4.9 (c) 5.0 (d) 5.2
  12. 12.Best estimate of 892 ÷ 67? (a) 13 (b) 130 (c) 1300
  13. 13.Best estimate of 7724 ÷ 89? (a) 860 (b) 8600 (c) 86
  14. 14.√82 to 1 decimal place? (a) 9.3 (b) 9.0 (c) 9.2 (d) 9.1
  15. 15.Best estimate of 2312 ÷ 38? (a) 5800 (b) 58 (c) 580
  16. 16.Best estimate of 3240 ÷ 48? (a) 650 (b) 65 (c) 6500
  17. 17.Best estimate of 6549 ÷ 73? (a) 94 (b) 940 (c) 9400
  18. 18.Best estimate of 1727 ÷ 81? (a) 2200 (b) 22 (c) 220
  19. 19.Best estimate of 1170 ÷ 53? (a) 23 (b) 230 (c) 2300
  20. 20.Best estimate of 5368 ÷ 76? (a) 67 (b) 6700 (c) 670
  21. 21.Best estimate of 2948 ÷ 36? (a) 740 (b) 7400 (c) 74
  22. 22.√31 to 1 decimal place? (a) 5.7 (b) 5.5 (c) 5.6 (d) 5.8
  23. 23.Best estimate of 2131 ÷ 56? (a) 3600 (b) 36 (c) 360
  24. 24.Best estimate of 4685 ÷ 82? (a) 590 (b) 59 (c) 5900
  25. 25.√27 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.2 (d) 5.0
  26. 26.√38 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.3 (d) 6.0
  27. 27.√26 to 1 decimal place? (a) 5.3 (b) 5.2 (c) 5.1 (d) 5.4
  28. 28.√69 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.5 (d) 8.6
  29. 29.Best estimate of 3437 ÷ 84? (a) 4300 (b) 43 (c) 430
  30. 30.√88 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.1 (d) 9.2
  31. 31.√32 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 5.7 (d) 5.9
  32. 32.√40 to 1 decimal place? (a) 6.2 (b) 6.5 (c) 6.3 (d) 6.4
  33. 33.Best estimate of 3642 ÷ 61? (a) 61 (b) 610 (c) 6100
  34. 34.√37 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 6.2 (d) 5.9
  35. 35.Best estimate of 3906 ÷ 72? (a) 560 (b) 5600 (c) 56
  36. 36.Best estimate of 1014 ÷ 59? (a) 170 (b) 17 (c) 1700
  37. 37.√72 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.3 (d) 8.4
  38. 38.√59 to 1 decimal place? (a) 8.0 (b) 7.7 (c) 7.8 (d) 7.9
  39. 39.Best estimate of 2229 ÷ 33? (a) 740 (b) 7400 (c) 74
  40. 40.√34 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 5.7 (d) 6.0

Answer key

  1. 5.3
  2. 47
  3. 6.4
  4. 9.6
  5. 60
  6. 21
  7. 66
  8. 7.4
  9. 70
  10. 33
  11. 4.9
  12. 13
  13. 86
  14. 9.1
  15. 58
  16. 65
  17. 94
  18. 22
  19. 23
  20. 67
  21. 74
  22. 5.6
  23. 36
  24. 59
  25. 5.2
  26. 6.2
  27. 5.1
  28. 8.3
  29. 43
  30. 9.4
  31. 5.7
  32. 6.3
  33. 61
  34. 6.1
  35. 56
  36. 17
  37. 8.5
  38. 7.7
  39. 74
  40. 5.8

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