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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 294 · 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 418 ÷ 29? (a) 14 (b) 1400 (c) 140
  2. 2.Best estimate of 924 ÷ 37? (a) 230 (b) 23 (c) 2300
  3. 3.√74 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.3 (d) 8.6
  4. 4.Best estimate of 2476 ÷ 33? (a) 830 (b) 83 (c) 8300
  5. 5.√89 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.4
  6. 6.Best estimate of 1164 ÷ 54? (a) 230 (b) 2300 (c) 23
  7. 7.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 8.9 (d) 9.0
  8. 8.Best estimate of 7403 ÷ 87? (a) 8200 (b) 82 (c) 820
  9. 9.Best estimate of 4336 ÷ 76? (a) 540 (b) 54 (c) 5400
  10. 10.Best estimate of 2564 ÷ 52? (a) 5100 (b) 510 (c) 51
  11. 11.√31 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.6 (d) 5.9
  12. 12.√65 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 7.8 (d) 7.9
  13. 13.Best estimate of 3400 ÷ 86? (a) 380 (b) 38 (c) 3800
  14. 14.Best estimate of 864 ÷ 26? (a) 29 (b) 2900 (c) 290
  15. 15.√69 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 8.3 (d) 8.1
  16. 16.√29 to 1 decimal place? (a) 5.3 (b) 5.5 (c) 5.6 (d) 5.4
  17. 17.Best estimate of 4176 ÷ 56? (a) 70 (b) 7000 (c) 700
  18. 18.√61 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.8
  19. 19.√27 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.3 (d) 5.0
  20. 20.√79 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.2 (d) 8.9
  21. 21.Best estimate of 2036 ÷ 22? (a) 1020 (b) 102 (c) 10200
  22. 22.Best estimate of 2101 ÷ 32? (a) 700 (b) 7000 (c) 70
  23. 23.Best estimate of 4936 ÷ 58? (a) 82 (b) 8200 (c) 820
  24. 24.√35 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 5.7
  25. 25.Best estimate of 2339 ÷ 78? (a) 290 (b) 2900 (c) 29
  26. 26.√30 to 1 decimal place? (a) 5.5 (b) 5.2 (c) 5.3 (d) 5.4
  27. 27.Best estimate of 4892 ÷ 67? (a) 700 (b) 70 (c) 7000
  28. 28.Best estimate of 5832 ÷ 79? (a) 73 (b) 7300 (c) 730
  29. 29.Best estimate of 620 ÷ 24? (a) 3100 (b) 31 (c) 310
  30. 30.Best estimate of 624 ÷ 44? (a) 16 (b) 160 (c) 1600
  31. 31.√80 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.9 (d) 8.8
  32. 32.√67 to 1 decimal place? (a) 7.9 (b) 8.2 (c) 8.0 (d) 8.1
  33. 33.Best estimate of 2204 ÷ 81? (a) 280 (b) 2800 (c) 28
  34. 34.√42 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.6 (d) 6.4
  35. 35.Best estimate of 3688 ÷ 41? (a) 92 (b) 920 (c) 9200
  36. 36.√58 to 1 decimal place? (a) 7.8 (b) 7.5 (c) 7.6 (d) 7.7
  37. 37.Best estimate of 1758 ÷ 36? (a) 4400 (b) 44 (c) 440
  38. 38.Best estimate of 2090 ÷ 72? (a) 30 (b) 3000 (c) 300
  39. 39.√70 to 1 decimal place? (a) 8.5 (b) 8.3 (c) 8.2 (d) 8.4
  40. 40.√32 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.7 (d) 5.8

Answer key

  1. 14
  2. 23
  3. 8.6
  4. 83
  5. 9.4
  6. 23
  7. 9.1
  8. 82
  9. 54
  10. 51
  11. 5.6
  12. 8.1
  13. 38
  14. 29
  15. 8.3
  16. 5.4
  17. 70
  18. 7.8
  19. 5.2
  20. 8.9
  21. 102
  22. 70
  23. 82
  24. 5.9
  25. 29
  26. 5.5
  27. 70
  28. 73
  29. 31
  30. 16
  31. 8.9
  32. 8.2
  33. 28
  34. 6.5
  35. 92
  36. 7.6
  37. 44
  38. 30
  39. 8.4
  40. 5.7

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