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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 559 · 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.√67 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.3 (d) 8.5
  2. 2.Best estimate of 290 ÷ 21? (a) 1500 (b) 15 (c) 150
  3. 3.√92 to 1 decimal place? (a) 9.6 (b) 9.9 (c) 9.8 (d) 9.7
  4. 4.√59 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.7 (d) 7.6
  5. 5.Best estimate of 6633 ÷ 72? (a) 9500 (b) 950 (c) 95
  6. 6.√35 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 5.9
  7. 7.√29 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.6 (d) 5.7
  8. 8.Best estimate of 614 ÷ 22? (a) 31 (b) 3100 (c) 310
  9. 9.√21 to 1 decimal place? (a) 4.7 (b) 4.6 (c) 4.5 (d) 4.4
  10. 10.Best estimate of 2769 ÷ 42? (a) 690 (b) 69 (c) 6900
  11. 11.Best estimate of 3244 ÷ 72? (a) 460 (b) 4600 (c) 46
  12. 12.√74 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.6 (d) 8.3
  13. 13.Best estimate of 2440 ÷ 41? (a) 61 (b) 610 (c) 6100
  14. 14.Best estimate of 4262 ÷ 57? (a) 7100 (b) 71 (c) 710
  15. 15.√69 to 1 decimal place? (a) 8.3 (b) 8.1 (c) 8.2 (d) 8.4
  16. 16.√55 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.7 (d) 7.4
  17. 17.Best estimate of 2821 ÷ 31? (a) 9400 (b) 94 (c) 940
  18. 18.√94 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.6 (d) 9.7
  19. 19.Best estimate of 4754 ÷ 57? (a) 790 (b) 7900 (c) 79
  20. 20.√37 to 1 decimal place? (a) 6.1 (b) 5.8 (c) 6.0 (d) 5.9
  21. 21.√89 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.1 (d) 9.2
  22. 22.√42 to 1 decimal place? (a) 6.5 (b) 6.2 (c) 6.4 (d) 6.3
  23. 23.Best estimate of 6504 ÷ 89? (a) 72 (b) 7200 (c) 720
  24. 24.Best estimate of 2480 ÷ 29? (a) 83 (b) 8300 (c) 830
  25. 25.Best estimate of 6391 ÷ 84? (a) 80 (b) 800 (c) 8000
  26. 26.Best estimate of 1563 ÷ 68? (a) 220 (b) 2200 (c) 22
  27. 27.√52 to 1 decimal place? (a) 6.9 (b) 7.2 (c) 7.0 (d) 7.1
  28. 28.Best estimate of 1084 ÷ 36? (a) 2700 (b) 27 (c) 270
  29. 29.Best estimate of 1735 ÷ 48? (a) 3500 (b) 35 (c) 350
  30. 30.Best estimate of 7515 ÷ 83? (a) 9400 (b) 940 (c) 94
  31. 31.√63 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 8.0 (d) 8.1
  32. 32.Best estimate of 898 ÷ 56? (a) 1500 (b) 15 (c) 150
  33. 33.√34 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 5.8 (d) 6.1
  34. 34.Best estimate of 1082 ÷ 63? (a) 18 (b) 180 (c) 1800
  35. 35.Best estimate of 1280 ÷ 56? (a) 2100 (b) 210 (c) 21
  36. 36.√98 to 1 decimal place? (a) 9.9 (b) 10.2 (c) 10.0 (d) 10.1
  37. 37.Best estimate of 2583 ÷ 27? (a) 860 (b) 86 (c) 8600
  38. 38.√62 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 7.6 (d) 7.8
  39. 39.Best estimate of 2320 ÷ 89? (a) 2600 (b) 26 (c) 260
  40. 40.Best estimate of 4354 ÷ 64? (a) 730 (b) 7300 (c) 73

Answer key

  1. 8.2
  2. 15
  3. 9.6
  4. 7.7
  5. 95
  6. 5.9
  7. 5.4
  8. 31
  9. 4.6
  10. 69
  11. 46
  12. 8.6
  13. 61
  14. 71
  15. 8.3
  16. 7.4
  17. 94
  18. 9.7
  19. 79
  20. 6.1
  21. 9.4
  22. 6.5
  23. 72
  24. 83
  25. 80
  26. 22
  27. 7.2
  28. 27
  29. 35
  30. 94
  31. 7.9
  32. 15
  33. 5.8
  34. 18
  35. 21
  36. 9.9
  37. 86
  38. 7.9
  39. 26
  40. 73

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