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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 235 · 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 2167 ÷ 31? (a) 72 (b) 720 (c) 7200
  2. 2.√35 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 5.8 (d) 5.6
  3. 3.√24 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 4.9 (d) 4.8
  4. 4.Best estimate of 3239 ÷ 57? (a) 54 (b) 540 (c) 5400
  5. 5.Best estimate of 1018 ÷ 47? (a) 200 (b) 2000 (c) 20
  6. 6.Best estimate of 2282 ÷ 51? (a) 46 (b) 460 (c) 4600
  7. 7.√82 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 9.0 (d) 9.1
  8. 8.Best estimate of 3053 ÷ 83? (a) 380 (b) 38 (c) 3800
  9. 9.Best estimate of 1023 ÷ 23? (a) 5100 (b) 510 (c) 51
  10. 10.Best estimate of 1048 ÷ 56? (a) 170 (b) 1700 (c) 17
  11. 11.√20 to 1 decimal place? (a) 4.5 (b) 4.4 (c) 4.3 (d) 4.6
  12. 12.√34 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 5.9 (d) 5.8
  13. 13.Best estimate of 4116 ÷ 77? (a) 5100 (b) 510 (c) 51
  14. 14.√45 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.7 (d) 6.5
  15. 15.Best estimate of 6498 ÷ 77? (a) 810 (b) 81 (c) 8100
  16. 16.√69 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.4 (d) 8.6
  17. 17.Best estimate of 3869 ÷ 69? (a) 550 (b) 5500 (c) 55
  18. 18.√51 to 1 decimal place? (a) 7.1 (b) 7.3 (c) 7.0 (d) 7.2
  19. 19.Best estimate of 565 ÷ 32? (a) 19 (b) 1900 (c) 190
  20. 20.Best estimate of 2450 ÷ 29? (a) 820 (b) 8200 (c) 82
  21. 21.Best estimate of 1871 ÷ 27? (a) 62 (b) 620 (c) 6200
  22. 22.Best estimate of 3626 ÷ 56? (a) 60 (b) 600 (c) 6000
  23. 23.Best estimate of 2591 ÷ 66? (a) 37 (b) 370 (c) 3700
  24. 24.Best estimate of 1206 ÷ 58? (a) 200 (b) 2000 (c) 20
  25. 25.Best estimate of 1980 ÷ 36? (a) 50 (b) 5000 (c) 500
  26. 26.√87 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.5 (d) 9.3
  27. 27.√74 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  28. 28.Best estimate of 3663 ÷ 77? (a) 460 (b) 46 (c) 4600
  29. 29.√42 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.5 (d) 6.4
  30. 30.√26 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.4 (d) 5.3
  31. 31.Best estimate of 971 ÷ 54? (a) 1900 (b) 19 (c) 190
  32. 32.√94 to 1 decimal place? (a) 10.0 (b) 9.8 (c) 9.7 (d) 9.9
  33. 33.Best estimate of 478 ÷ 28? (a) 1600 (b) 16 (c) 160
  34. 34.√65 to 1 decimal place? (a) 8.1 (b) 8.4 (c) 8.3 (d) 8.2
  35. 35.√66 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 8.2 (d) 8.1
  36. 36.Best estimate of 1099 ÷ 59? (a) 180 (b) 1800 (c) 18
  37. 37.√72 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  38. 38.√55 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.7 (d) 7.5
  39. 39.Best estimate of 2965 ÷ 36? (a) 74 (b) 740 (c) 7400
  40. 40.Best estimate of 1259 ÷ 32? (a) 420 (b) 4200 (c) 42

Answer key

  1. 72
  2. 5.9
  3. 4.9
  4. 54
  5. 20
  6. 46
  7. 9.1
  8. 38
  9. 51
  10. 17
  11. 4.5
  12. 5.8
  13. 51
  14. 6.7
  15. 81
  16. 8.3
  17. 55
  18. 7.1
  19. 19
  20. 82
  21. 62
  22. 60
  23. 37
  24. 20
  25. 50
  26. 9.3
  27. 8.6
  28. 46
  29. 6.5
  30. 5.1
  31. 19
  32. 9.7
  33. 16
  34. 8.1
  35. 8.1
  36. 18
  37. 8.5
  38. 7.4
  39. 74
  40. 42

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