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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 220 · 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.√77 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.6 (d) 8.5
  2. 2.√76 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.4 (d) 8.7
  3. 3.Best estimate of 2019 ÷ 46? (a) 400 (b) 4000 (c) 40
  4. 4.√45 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.9 (d) 6.7
  5. 5.√86 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 9.3 (d) 9.1
  6. 6.Best estimate of 1395 ÷ 44? (a) 350 (b) 3500 (c) 35
  7. 7.Best estimate of 2467 ÷ 31? (a) 820 (b) 82 (c) 8200
  8. 8.√47 to 1 decimal place? (a) 6.6 (b) 6.9 (c) 6.7 (d) 6.8
  9. 9.√59 to 1 decimal place? (a) 7.7 (b) 7.4 (c) 7.5 (d) 7.6
  10. 10.Best estimate of 2249 ÷ 42? (a) 560 (b) 5600 (c) 56
  11. 11.Best estimate of 3504 ÷ 42? (a) 88 (b) 8800 (c) 880
  12. 12.√88 to 1 decimal place? (a) 9.5 (b) 9.2 (c) 9.3 (d) 9.4
  13. 13.Best estimate of 6939 ÷ 89? (a) 7700 (b) 770 (c) 77
  14. 14.√67 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.3 (d) 8.4
  15. 15.Best estimate of 2435 ÷ 74? (a) 350 (b) 35 (c) 3500
  16. 16.√29 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.3 (d) 5.4
  17. 17.Best estimate of 4242 ÷ 89? (a) 470 (b) 47 (c) 4700
  18. 18.√82 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.8 (d) 8.9
  19. 19.√98 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.6 (d) 9.7
  20. 20.√40 to 1 decimal place? (a) 6.3 (b) 6.5 (c) 6.6 (d) 6.4
  21. 21.Best estimate of 2441 ÷ 66? (a) 350 (b) 35 (c) 3500
  22. 22.√78 to 1 decimal place? (a) 9.1 (b) 8.8 (c) 9.0 (d) 8.9
  23. 23.√90 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.5 (d) 9.7
  24. 24.Best estimate of 795 ÷ 42? (a) 200 (b) 20 (c) 2000
  25. 25.Best estimate of 3183 ÷ 42? (a) 80 (b) 800 (c) 8000
  26. 26.√74 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  27. 27.Best estimate of 4785 ÷ 52? (a) 96 (b) 960 (c) 9600
  28. 28.Best estimate of 631 ÷ 21? (a) 320 (b) 32 (c) 3200
  29. 29.√44 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.5 (d) 6.8
  30. 30.Best estimate of 4953 ÷ 82? (a) 620 (b) 62 (c) 6200
  31. 31.√26 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 4.9 (d) 4.8
  32. 32.√42 to 1 decimal place? (a) 6.5 (b) 6.8 (c) 6.6 (d) 6.7
  33. 33.Best estimate of 2911 ÷ 36? (a) 7300 (b) 73 (c) 730
  34. 34.√37 to 1 decimal place? (a) 6.4 (b) 6.1 (c) 6.3 (d) 6.2
  35. 35.Best estimate of 763 ÷ 54? (a) 15 (b) 150 (c) 1500
  36. 36.√50 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.0 (d) 7.3
  37. 37.Best estimate of 2300 ÷ 32? (a) 770 (b) 77 (c) 7700
  38. 38.Best estimate of 626 ÷ 26? (a) 2100 (b) 21 (c) 210
  39. 39.√41 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.4 (d) 6.5
  40. 40.Best estimate of 4585 ÷ 64? (a) 7600 (b) 76 (c) 760

Answer key

  1. 8.8
  2. 8.7
  3. 40
  4. 6.7
  5. 9.3
  6. 35
  7. 82
  8. 6.9
  9. 7.7
  10. 56
  11. 88
  12. 9.4
  13. 77
  14. 8.2
  15. 35
  16. 5.4
  17. 47
  18. 9.1
  19. 9.9
  20. 6.3
  21. 35
  22. 8.8
  23. 9.5
  24. 20
  25. 80
  26. 8.6
  27. 96
  28. 32
  29. 6.6
  30. 62
  31. 5.1
  32. 6.5
  33. 73
  34. 6.1
  35. 15
  36. 7.1
  37. 77
  38. 21
  39. 6.4
  40. 76

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