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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 679 · 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.√41 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.4 (d) 6.5
  2. 2.√76 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.7 (d) 8.9
  3. 3.Best estimate of 1881 ÷ 88? (a) 21 (b) 2100 (c) 210
  4. 4.√29 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.6 (d) 5.7
  5. 5.Best estimate of 3775 ÷ 52? (a) 760 (b) 7600 (c) 76
  6. 6.Best estimate of 2987 ÷ 41? (a) 750 (b) 7500 (c) 75
  7. 7.Best estimate of 1203 ÷ 76? (a) 1500 (b) 150 (c) 15
  8. 8.Best estimate of 564 ÷ 37? (a) 1400 (b) 140 (c) 14
  9. 9.Best estimate of 7432 ÷ 88? (a) 83 (b) 830 (c) 8300
  10. 10.√75 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.8 (d) 8.5
  11. 11.Best estimate of 2623 ÷ 37? (a) 6600 (b) 66 (c) 660
  12. 12.√53 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.4 (d) 7.3
  13. 13.Best estimate of 6202 ÷ 87? (a) 69 (b) 690 (c) 6900
  14. 14.Best estimate of 5203 ÷ 57? (a) 870 (b) 87 (c) 8700
  15. 15.√77 to 1 decimal place? (a) 8.8 (b) 9.0 (c) 9.1 (d) 8.9
  16. 16.Best estimate of 1595 ÷ 61? (a) 270 (b) 27 (c) 2700
  17. 17.Best estimate of 4372 ÷ 74? (a) 62 (b) 6200 (c) 620
  18. 18.Best estimate of 821 ÷ 31? (a) 27 (b) 2700 (c) 270
  19. 19.Best estimate of 2674 ÷ 72? (a) 380 (b) 38 (c) 3800
  20. 20.Best estimate of 7525 ÷ 84? (a) 940 (b) 9400 (c) 94
  21. 21.Best estimate of 3665 ÷ 48? (a) 73 (b) 730 (c) 7300
  22. 22.√40 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  23. 23.Best estimate of 2659 ÷ 46? (a) 530 (b) 53 (c) 5300
  24. 24.Best estimate of 1521 ÷ 63? (a) 25 (b) 2500 (c) 250
  25. 25.Best estimate of 5663 ÷ 61? (a) 940 (b) 94 (c) 9400
  26. 26.√34 to 1 decimal place? (a) 6.1 (b) 5.8 (c) 6.0 (d) 5.9
  27. 27.Best estimate of 3997 ÷ 62? (a) 6700 (b) 67 (c) 670
  28. 28.Best estimate of 1056 ÷ 29? (a) 35 (b) 3500 (c) 350
  29. 29.Best estimate of 2600 ÷ 33? (a) 870 (b) 87 (c) 8700
  30. 30.√70 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.5 (d) 8.7
  31. 31.√45 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.7 (d) 6.8
  32. 32.Best estimate of 944 ÷ 26? (a) 31 (b) 3100 (c) 310
  33. 33.Best estimate of 5913 ÷ 73? (a) 840 (b) 8400 (c) 84
  34. 34.Best estimate of 3795 ÷ 41? (a) 9500 (b) 950 (c) 95
  35. 35.√79 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  36. 36.Best estimate of 2027 ÷ 46? (a) 410 (b) 41 (c) 4100
  37. 37.Best estimate of 883 ÷ 52? (a) 180 (b) 1800 (c) 18
  38. 38.Best estimate of 6900 ÷ 78? (a) 860 (b) 86 (c) 8600
  39. 39.Best estimate of 5565 ÷ 77? (a) 70 (b) 7000 (c) 700
  40. 40.√72 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.5 (d) 8.7

Answer key

  1. 6.4
  2. 8.7
  3. 21
  4. 5.4
  5. 76
  6. 75
  7. 15
  8. 14
  9. 83
  10. 8.7
  11. 66
  12. 7.3
  13. 69
  14. 87
  15. 8.8
  16. 27
  17. 62
  18. 27
  19. 38
  20. 94
  21. 73
  22. 6.3
  23. 53
  24. 25
  25. 94
  26. 5.8
  27. 67
  28. 35
  29. 87
  30. 8.4
  31. 6.7
  32. 31
  33. 84
  34. 95
  35. 8.9
  36. 41
  37. 18
  38. 86
  39. 70
  40. 8.5

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