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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 532 · 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 1872 ÷ 54? (a) 37 (b) 370 (c) 3700
  2. 2.Best estimate of 3802 ÷ 43? (a) 950 (b) 9500 (c) 95
  3. 3.√80 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.9 (d) 8.8
  4. 4.√61 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.9 (d) 7.6
  5. 5.Best estimate of 1579 ÷ 54? (a) 3200 (b) 32 (c) 320
  6. 6.Best estimate of 3038 ÷ 59? (a) 510 (b) 51 (c) 5100
  7. 7.√92 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.9 (d) 9.6
  8. 8.Best estimate of 2707 ÷ 32? (a) 90 (b) 900 (c) 9000
  9. 9.Best estimate of 4058 ÷ 87? (a) 4500 (b) 450 (c) 45
  10. 10.Best estimate of 3529 ÷ 41? (a) 880 (b) 88 (c) 8800
  11. 11.Best estimate of 4638 ÷ 72? (a) 66 (b) 6600 (c) 660
  12. 12.√32 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.9 (d) 5.6
  13. 13.√66 to 1 decimal place? (a) 8.1 (b) 8.4 (c) 8.2 (d) 8.3
  14. 14.√27 to 1 decimal place? (a) 5.2 (b) 5.5 (c) 5.4 (d) 5.3
  15. 15.√74 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.9 (d) 8.8
  16. 16.√50 to 1 decimal place? (a) 7.1 (b) 6.9 (c) 7.2 (d) 7.0
  17. 17.√45 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.4 (d) 6.6
  18. 18.√63 to 1 decimal place? (a) 7.6 (b) 7.9 (c) 7.7 (d) 7.8
  19. 19.√69 to 1 decimal place? (a) 8.3 (b) 8.1 (c) 8.2 (d) 8.0
  20. 20.Best estimate of 1404 ÷ 42? (a) 3500 (b) 350 (c) 35
  21. 21.√90 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.4 (d) 9.5
  22. 22.Best estimate of 3765 ÷ 62? (a) 6300 (b) 630 (c) 63
  23. 23.√47 to 1 decimal place? (a) 7.0 (b) 6.8 (c) 6.9 (d) 6.7
  24. 24.√22 to 1 decimal place? (a) 5.0 (b) 4.8 (c) 4.7 (d) 4.9
  25. 25.Best estimate of 7128 ÷ 76? (a) 890 (b) 8900 (c) 89
  26. 26.Best estimate of 1621 ÷ 76? (a) 20 (b) 200 (c) 2000
  27. 27.Best estimate of 7423 ÷ 81? (a) 930 (b) 9300 (c) 93
  28. 28.Best estimate of 2141 ÷ 43? (a) 540 (b) 5400 (c) 54
  29. 29.Best estimate of 2514 ÷ 28? (a) 84 (b) 840 (c) 8400
  30. 30.Best estimate of 1484 ÷ 52? (a) 300 (b) 30 (c) 3000
  31. 31.Best estimate of 6762 ÷ 84? (a) 850 (b) 8500 (c) 85
  32. 32.Best estimate of 1086 ÷ 39? (a) 2700 (b) 270 (c) 27
  33. 33.Best estimate of 309 ÷ 22? (a) 15 (b) 150 (c) 1500
  34. 34.Best estimate of 6684 ÷ 76? (a) 840 (b) 84 (c) 8400
  35. 35.√42 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.7 (d) 6.5
  36. 36.√65 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.2 (d) 8.1
  37. 37.Best estimate of 3464 ÷ 46? (a) 690 (b) 69 (c) 6900
  38. 38.Best estimate of 2012 ÷ 22? (a) 1010 (b) 10100 (c) 101
  39. 39.√58 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 7.7 (d) 7.6
  40. 40.√28 to 1 decimal place? (a) 5.0 (b) 5.2 (c) 5.3 (d) 5.1

Answer key

  1. 37
  2. 95
  3. 8.9
  4. 7.8
  5. 32
  6. 51
  7. 9.6
  8. 90
  9. 45
  10. 88
  11. 66
  12. 5.7
  13. 8.1
  14. 5.2
  15. 8.6
  16. 7.1
  17. 6.7
  18. 7.9
  19. 8.3
  20. 35
  21. 9.5
  22. 63
  23. 6.9
  24. 4.7
  25. 89
  26. 20
  27. 93
  28. 54
  29. 84
  30. 30
  31. 85
  32. 27
  33. 15
  34. 84
  35. 6.5
  36. 8.1
  37. 69
  38. 101
  39. 7.6
  40. 5.3

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