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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 517 · 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 3129 ÷ 67? (a) 45 (b) 4500 (c) 450
  2. 2.√59 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 7.8 (d) 7.7
  3. 3.Best estimate of 3441 ÷ 46? (a) 6900 (b) 690 (c) 69
  4. 4.√47 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.8 (d) 6.9
  5. 5.√58 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.5 (d) 7.8
  6. 6.Best estimate of 2212 ÷ 73? (a) 32 (b) 3200 (c) 320
  7. 7.√72 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  8. 8.Best estimate of 509 ÷ 24? (a) 250 (b) 25 (c) 2500
  9. 9.√45 to 1 decimal place? (a) 6.4 (b) 6.7 (c) 6.6 (d) 6.5
  10. 10.Best estimate of 2295 ÷ 87? (a) 26 (b) 260 (c) 2600
  11. 11.Best estimate of 6045 ÷ 71? (a) 8600 (b) 86 (c) 860
  12. 12.Best estimate of 2532 ÷ 43? (a) 630 (b) 63 (c) 6300
  13. 13.√65 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 7.9 (d) 8.1
  14. 14.Best estimate of 3989 ÷ 62? (a) 6600 (b) 660 (c) 66
  15. 15.Best estimate of 2299 ÷ 29? (a) 7700 (b) 770 (c) 77
  16. 16.√35 to 1 decimal place? (a) 6.1 (b) 5.9 (c) 5.8 (d) 6.0
  17. 17.√34 to 1 decimal place? (a) 5.8 (b) 6.1 (c) 6.0 (d) 5.9
  18. 18.Best estimate of 926 ÷ 54? (a) 1900 (b) 190 (c) 19
  19. 19.Best estimate of 2721 ÷ 66? (a) 3900 (b) 39 (c) 390
  20. 20.Best estimate of 2907 ÷ 33? (a) 97 (b) 970 (c) 9700
  21. 21.√69 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.5 (d) 8.3
  22. 22.Best estimate of 877 ÷ 64? (a) 15 (b) 150 (c) 1500
  23. 23.√96 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.6 (d) 9.9
  24. 24.Best estimate of 2852 ÷ 39? (a) 710 (b) 71 (c) 7100
  25. 25.Best estimate of 6030 ÷ 66? (a) 86 (b) 8600 (c) 860
  26. 26.√74 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.4 (d) 8.6
  27. 27.Best estimate of 6897 ÷ 82? (a) 860 (b) 86 (c) 8600
  28. 28.Best estimate of 3056 ÷ 44? (a) 760 (b) 76 (c) 7600
  29. 29.Best estimate of 1010 ÷ 57? (a) 17 (b) 170 (c) 1700
  30. 30.Best estimate of 2809 ÷ 74? (a) 4000 (b) 40 (c) 400
  31. 31.Best estimate of 2195 ÷ 84? (a) 270 (b) 2700 (c) 27
  32. 32.Best estimate of 1053 ÷ 69? (a) 150 (b) 15 (c) 1500
  33. 33.Best estimate of 4307 ÷ 53? (a) 8600 (b) 86 (c) 860
  34. 34.√55 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.7 (d) 7.4
  35. 35.Best estimate of 2782 ÷ 61? (a) 46 (b) 460 (c) 4600
  36. 36.√94 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.5 (d) 9.6
  37. 37.Best estimate of 603 ÷ 32? (a) 2000 (b) 200 (c) 20
  38. 38.√61 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 8.1 (d) 8.0
  39. 39.√80 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 9.2
  40. 40.Best estimate of 3899 ÷ 46? (a) 78 (b) 780 (c) 7800

Answer key

  1. 45
  2. 7.7
  3. 69
  4. 6.9
  5. 7.6
  6. 32
  7. 8.5
  8. 25
  9. 6.7
  10. 26
  11. 86
  12. 63
  13. 8.1
  14. 66
  15. 77
  16. 5.9
  17. 5.8
  18. 19
  19. 39
  20. 97
  21. 8.3
  22. 15
  23. 9.8
  24. 71
  25. 86
  26. 8.6
  27. 86
  28. 76
  29. 17
  30. 40
  31. 27
  32. 15
  33. 86
  34. 7.4
  35. 46
  36. 9.7
  37. 20
  38. 7.8
  39. 8.9
  40. 78

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