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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 870 · 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.√82 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.9 (d) 9.2
  2. 2.√43 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.6 (d) 6.7
  3. 3.√44 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.9 (d) 6.8
  4. 4.√34 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.6 (d) 5.5
  5. 5.√92 to 1 decimal place? (a) 9.4 (b) 9.7 (c) 9.6 (d) 9.5
  6. 6.√72 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  7. 7.Best estimate of 1868 ÷ 26? (a) 620 (b) 62 (c) 6200
  8. 8.Best estimate of 3000 ÷ 39? (a) 75 (b) 7500 (c) 750
  9. 9.Best estimate of 1169 ÷ 34? (a) 3900 (b) 390 (c) 39
  10. 10.√20 to 1 decimal place? (a) 4.2 (b) 4.4 (c) 4.5 (d) 4.3
  11. 11.√75 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 9.0 (d) 8.9
  12. 12.Best estimate of 2542 ÷ 56? (a) 42 (b) 420 (c) 4200
  13. 13.Best estimate of 6381 ÷ 82? (a) 8000 (b) 800 (c) 80
  14. 14.Best estimate of 3464 ÷ 41? (a) 870 (b) 8700 (c) 87
  15. 15.Best estimate of 3597 ÷ 81? (a) 4500 (b) 45 (c) 450
  16. 16.√38 to 1 decimal place? (a) 6.4 (b) 6.2 (c) 6.3 (d) 6.5
  17. 17.Best estimate of 2539 ÷ 32? (a) 85 (b) 850 (c) 8500
  18. 18.Best estimate of 707 ÷ 23? (a) 3500 (b) 35 (c) 350
  19. 19.√79 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.2 (d) 8.9
  20. 20.Best estimate of 1006 ÷ 27? (a) 3400 (b) 340 (c) 34
  21. 21.√62 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 7.6 (d) 7.8
  22. 22.Best estimate of 2601 ÷ 48? (a) 5200 (b) 520 (c) 52
  23. 23.√98 to 1 decimal place? (a) 10.1 (b) 10.2 (c) 10.0 (d) 9.9
  24. 24.Best estimate of 2408 ÷ 76? (a) 3000 (b) 30 (c) 300
  25. 25.Best estimate of 1798 ÷ 57? (a) 30 (b) 300 (c) 3000
  26. 26.√71 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.1 (d) 8.2
  27. 27.Best estimate of 1390 ÷ 58? (a) 230 (b) 2300 (c) 23
  28. 28.√37 to 1 decimal place? (a) 6.1 (b) 6.4 (c) 6.2 (d) 6.3
  29. 29.Best estimate of 790 ÷ 52? (a) 16 (b) 1600 (c) 160
  30. 30.Best estimate of 2737 ÷ 31? (a) 910 (b) 9100 (c) 91
  31. 31.Best estimate of 2784 ÷ 69? (a) 400 (b) 4000 (c) 40
  32. 32.√84 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 9.1 (d) 8.9
  33. 33.Best estimate of 5369 ÷ 66? (a) 770 (b) 77 (c) 7700
  34. 34.√55 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.5 (d) 7.7
  35. 35.Best estimate of 1099 ÷ 33? (a) 3700 (b) 370 (c) 37
  36. 36.Best estimate of 4304 ÷ 53? (a) 86 (b) 8600 (c) 860
  37. 37.√87 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.5 (d) 9.6
  38. 38.Best estimate of 940 ÷ 39? (a) 240 (b) 2400 (c) 24
  39. 39.Best estimate of 2019 ÷ 29? (a) 67 (b) 670 (c) 6700
  40. 40.Best estimate of 1830 ÷ 32? (a) 61 (b) 610 (c) 6100

Answer key

  1. 9.1
  2. 6.6
  3. 6.6
  4. 5.8
  5. 9.6
  6. 8.5
  7. 62
  8. 75
  9. 39
  10. 4.5
  11. 8.7
  12. 42
  13. 80
  14. 87
  15. 45
  16. 6.2
  17. 85
  18. 35
  19. 8.9
  20. 34
  21. 7.9
  22. 52
  23. 9.9
  24. 30
  25. 30
  26. 8.4
  27. 23
  28. 6.1
  29. 16
  30. 91
  31. 40
  32. 9.2
  33. 77
  34. 7.4
  35. 37
  36. 86
  37. 9.3
  38. 24
  39. 67
  40. 61

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