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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 272 · 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 2357 ÷ 86? (a) 260 (b) 26 (c) 2600
  2. 2.√75 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 9.0 (d) 8.7
  3. 3.√52 to 1 decimal place? (a) 7.5 (b) 7.2 (c) 7.4 (d) 7.3
  4. 4.Best estimate of 2321 ÷ 38? (a) 5800 (b) 58 (c) 580
  5. 5.Best estimate of 2139 ÷ 36? (a) 53 (b) 530 (c) 5300
  6. 6.√76 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.6 (d) 8.4
  7. 7.Best estimate of 4902 ÷ 72? (a) 700 (b) 70 (c) 7000
  8. 8.√83 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.1 (d) 9.3
  9. 9.Best estimate of 5875 ÷ 86? (a) 650 (b) 65 (c) 6500
  10. 10.√74 to 1 decimal place? (a) 8.6 (b) 8.9 (c) 8.7 (d) 8.8
  11. 11.√45 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.8 (d) 6.5
  12. 12.√66 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.0 (d) 8.1
  13. 13.√20 to 1 decimal place? (a) 4.5 (b) 4.6 (c) 4.7 (d) 4.4
  14. 14.Best estimate of 3503 ÷ 76? (a) 44 (b) 440 (c) 4400
  15. 15.Best estimate of 762 ÷ 27? (a) 2500 (b) 250 (c) 25
  16. 16.Best estimate of 2494 ÷ 34? (a) 8300 (b) 830 (c) 83
  17. 17.√72 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.5 (d) 8.3
  18. 18.Best estimate of 2540 ÷ 88? (a) 280 (b) 28 (c) 2800
  19. 19.Best estimate of 1695 ÷ 72? (a) 2400 (b) 240 (c) 24
  20. 20.√88 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.3 (d) 9.5
  21. 21.√28 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.4 (d) 5.5
  22. 22.√32 to 1 decimal place? (a) 5.4 (b) 5.7 (c) 5.6 (d) 5.5
  23. 23.√67 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.5 (d) 8.2
  24. 24.√46 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 7.1 (d) 6.8
  25. 25.√96 to 1 decimal place? (a) 9.9 (b) 10.1 (c) 10.0 (d) 9.8
  26. 26.√87 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.0 (d) 9.2
  27. 27.√78 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 8.8 (d) 9.1
  28. 28.Best estimate of 3889 ÷ 54? (a) 78 (b) 7800 (c) 780
  29. 29.Best estimate of 2503 ÷ 41? (a) 63 (b) 630 (c) 6300
  30. 30.Best estimate of 3295 ÷ 87? (a) 3700 (b) 370 (c) 37
  31. 31.√63 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 7.7 (d) 7.6
  32. 32.√80 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.6 (d) 8.9
  33. 33.Best estimate of 5330 ÷ 56? (a) 8900 (b) 89 (c) 890
  34. 34.Best estimate of 4587 ÷ 54? (a) 9200 (b) 920 (c) 92
  35. 35.√82 to 1 decimal place? (a) 9.0 (b) 9.3 (c) 9.1 (d) 9.2
  36. 36.√69 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.5 (d) 8.4
  37. 37.Best estimate of 2032 ÷ 23? (a) 1020 (b) 10200 (c) 102
  38. 38.Best estimate of 3002 ÷ 89? (a) 3300 (b) 330 (c) 33
  39. 39.√94 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.9 (d) 9.8
  40. 40.Best estimate of 1575 ÷ 52? (a) 32 (b) 3200 (c) 320

Answer key

  1. 26
  2. 8.7
  3. 7.2
  4. 58
  5. 53
  6. 8.7
  7. 70
  8. 9.1
  9. 65
  10. 8.6
  11. 6.7
  12. 8.1
  13. 4.5
  14. 44
  15. 25
  16. 83
  17. 8.5
  18. 28
  19. 24
  20. 9.4
  21. 5.3
  22. 5.7
  23. 8.2
  24. 6.8
  25. 9.8
  26. 9.3
  27. 8.8
  28. 78
  29. 63
  30. 37
  31. 7.9
  32. 8.9
  33. 89
  34. 92
  35. 9.1
  36. 8.3
  37. 102
  38. 33
  39. 9.7
  40. 32

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