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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 670 · 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.√38 to 1 decimal place? (a) 6.5 (b) 6.2 (c) 6.3 (d) 6.4
  2. 2.Best estimate of 2629 ÷ 73? (a) 38 (b) 380 (c) 3800
  3. 3.Best estimate of 2313 ÷ 31? (a) 7700 (b) 77 (c) 770
  4. 4.Best estimate of 3215 ÷ 57? (a) 540 (b) 5400 (c) 54
  5. 5.Best estimate of 4193 ÷ 89? (a) 470 (b) 47 (c) 4700
  6. 6.√83 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 9.2 (d) 9.1
  7. 7.√52 to 1 decimal place? (a) 7.2 (b) 7.4 (c) 7.5 (d) 7.3
  8. 8.√70 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.3 (d) 8.4
  9. 9.Best estimate of 1875 ÷ 23? (a) 9400 (b) 940 (c) 94
  10. 10.Best estimate of 6648 ÷ 81? (a) 8300 (b) 83 (c) 830
  11. 11.Best estimate of 1478 ÷ 21? (a) 7400 (b) 740 (c) 74
  12. 12.√47 to 1 decimal place? (a) 7.1 (b) 7.0 (c) 6.9 (d) 7.2
  13. 13.√43 to 1 decimal place? (a) 6.5 (b) 6.3 (c) 6.6 (d) 6.4
  14. 14.√85 to 1 decimal place? (a) 9.4 (b) 9.1 (c) 9.3 (d) 9.2
  15. 15.Best estimate of 3434 ÷ 76? (a) 430 (b) 4300 (c) 43
  16. 16.√28 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.3 (d) 5.4
  17. 17.Best estimate of 871 ÷ 38? (a) 220 (b) 2200 (c) 22
  18. 18.√35 to 1 decimal place? (a) 5.9 (b) 6.2 (c) 6.1 (d) 6.0
  19. 19.Best estimate of 1187 ÷ 27? (a) 4000 (b) 40 (c) 400
  20. 20.Best estimate of 4160 ÷ 76? (a) 52 (b) 5200 (c) 520
  21. 21.Best estimate of 3849 ÷ 69? (a) 5500 (b) 550 (c) 55
  22. 22.√45 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.8 (d) 6.9
  23. 23.Best estimate of 7081 ÷ 78? (a) 890 (b) 8900 (c) 89
  24. 24.Best estimate of 1244 ÷ 73? (a) 1800 (b) 180 (c) 18
  25. 25.√65 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.1 (d) 8.3
  26. 26.Best estimate of 728 ÷ 42? (a) 180 (b) 1800 (c) 18
  27. 27.Best estimate of 465 ÷ 37? (a) 1200 (b) 12 (c) 120
  28. 28.Best estimate of 751 ÷ 36? (a) 1900 (b) 19 (c) 190
  29. 29.√41 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.7 (d) 6.6
  30. 30.√24 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 4.8 (d) 4.7
  31. 31.√72 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.8 (d) 8.7
  32. 32.√94 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.8
  33. 33.Best estimate of 4657 ÷ 58? (a) 7800 (b) 780 (c) 78
  34. 34.Best estimate of 5604 ÷ 62? (a) 930 (b) 93 (c) 9300
  35. 35.Best estimate of 6032 ÷ 88? (a) 670 (b) 6700 (c) 67
  36. 36.√20 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 4.6 (d) 4.5
  37. 37.Best estimate of 2147 ÷ 68? (a) 310 (b) 31 (c) 3100
  38. 38.Best estimate of 2040 ÷ 23? (a) 102 (b) 1020 (c) 10200
  39. 39.√32 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 5.7 (d) 5.9
  40. 40.Best estimate of 836 ÷ 44? (a) 21 (b) 2100 (c) 210

Answer key

  1. 6.2
  2. 38
  3. 77
  4. 54
  5. 47
  6. 9.1
  7. 7.2
  8. 8.4
  9. 94
  10. 83
  11. 74
  12. 6.9
  13. 6.6
  14. 9.2
  15. 43
  16. 5.3
  17. 22
  18. 5.9
  19. 40
  20. 52
  21. 55
  22. 6.7
  23. 89
  24. 18
  25. 8.1
  26. 18
  27. 12
  28. 19
  29. 6.4
  30. 4.9
  31. 8.5
  32. 9.7
  33. 78
  34. 93
  35. 67
  36. 4.5
  37. 31
  38. 102
  39. 5.7
  40. 21

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