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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 976 · 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.√62 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 7.8 (d) 7.9
  2. 2.Best estimate of 5980 ÷ 82? (a) 7500 (b) 75 (c) 750
  3. 3.Best estimate of 3431 ÷ 64? (a) 570 (b) 57 (c) 5700
  4. 4.Best estimate of 3984 ÷ 79? (a) 5000 (b) 500 (c) 50
  5. 5.√82 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.0 (d) 9.2
  6. 6.Best estimate of 614 ÷ 24? (a) 3100 (b) 310 (c) 31
  7. 7.√94 to 1 decimal place? (a) 9.5 (b) 9.6 (c) 9.8 (d) 9.7
  8. 8.Best estimate of 6052 ÷ 86? (a) 6700 (b) 67 (c) 670
  9. 9.√21 to 1 decimal place? (a) 4.6 (b) 4.7 (c) 4.9 (d) 4.8
  10. 10.Best estimate of 4654 ÷ 82? (a) 580 (b) 5800 (c) 58
  11. 11.Best estimate of 977 ÷ 31? (a) 33 (b) 3300 (c) 330
  12. 12.Best estimate of 3063 ÷ 32? (a) 1020 (b) 10200 (c) 102
  13. 13.Best estimate of 690 ÷ 23? (a) 35 (b) 350 (c) 3500
  14. 14.√37 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.3 (d) 6.0
  15. 15.√92 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.5 (d) 9.6
  16. 16.√56 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.7 (d) 7.8
  17. 17.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  18. 18.Best estimate of 490 ÷ 33? (a) 16 (b) 1600 (c) 160
  19. 19.Best estimate of 5967 ÷ 89? (a) 6600 (b) 660 (c) 66
  20. 20.√28 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.1 (d) 5.4
  21. 21.√66 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.0 (d) 8.2
  22. 22.Best estimate of 3687 ÷ 48? (a) 740 (b) 74 (c) 7400
  23. 23.Best estimate of 2818 ÷ 43? (a) 700 (b) 7000 (c) 70
  24. 24.Best estimate of 1201 ÷ 54? (a) 2400 (b) 240 (c) 24
  25. 25.Best estimate of 2740 ÷ 82? (a) 340 (b) 3400 (c) 34
  26. 26.Best estimate of 2992 ÷ 42? (a) 75 (b) 7500 (c) 750
  27. 27.√50 to 1 decimal place? (a) 7.1 (b) 6.9 (c) 7.0 (d) 7.2
  28. 28.Best estimate of 677 ÷ 36? (a) 1700 (b) 170 (c) 17
  29. 29.Best estimate of 752 ÷ 23? (a) 38 (b) 3800 (c) 380
  30. 30.Best estimate of 757 ÷ 46? (a) 15 (b) 150 (c) 1500
  31. 31.Best estimate of 576 ÷ 38? (a) 1400 (b) 14 (c) 140
  32. 32.Best estimate of 3121 ÷ 89? (a) 350 (b) 3500 (c) 35
  33. 33.Best estimate of 2467 ÷ 46? (a) 4900 (b) 490 (c) 49
  34. 34.√90 to 1 decimal place? (a) 9.3 (b) 9.6 (c) 9.4 (d) 9.5
  35. 35.Best estimate of 1952 ÷ 72? (a) 28 (b) 280 (c) 2800
  36. 36.√67 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.2 (d) 8.3
  37. 37.Best estimate of 817 ÷ 49? (a) 1600 (b) 16 (c) 160
  38. 38.√55 to 1 decimal place? (a) 7.2 (b) 7.4 (c) 7.3 (d) 7.1
  39. 39.Best estimate of 1959 ÷ 23? (a) 980 (b) 98 (c) 9800
  40. 40.√58 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.6 (d) 7.7

Answer key

  1. 7.9
  2. 75
  3. 57
  4. 50
  5. 9.1
  6. 31
  7. 9.7
  8. 67
  9. 4.6
  10. 58
  11. 33
  12. 102
  13. 35
  14. 6.1
  15. 9.6
  16. 7.5
  17. 8.7
  18. 16
  19. 66
  20. 5.3
  21. 8.1
  22. 74
  23. 70
  24. 24
  25. 34
  26. 75
  27. 7.1
  28. 17
  29. 38
  30. 15
  31. 14
  32. 35
  33. 49
  34. 9.5
  35. 28
  36. 8.2
  37. 16
  38. 7.4
  39. 98
  40. 7.6

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