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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 604 · 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.√69 to 1 decimal place? (a) 8.2 (b) 8.4 (c) 8.1 (d) 8.3
  2. 2.Best estimate of 3063 ÷ 32? (a) 10200 (b) 1020 (c) 102
  3. 3.Best estimate of 1066 ÷ 34? (a) 36 (b) 3600 (c) 360
  4. 4.Best estimate of 7277 ÷ 81? (a) 9100 (b) 91 (c) 910
  5. 5.Best estimate of 485 ÷ 39? (a) 1200 (b) 12 (c) 120
  6. 6.√22 to 1 decimal place? (a) 4.8 (b) 5.0 (c) 4.7 (d) 4.9
  7. 7.√92 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.5 (d) 9.7
  8. 8.Best estimate of 857 ÷ 56? (a) 14 (b) 140 (c) 1400
  9. 9.Best estimate of 3215 ÷ 49? (a) 640 (b) 64 (c) 6400
  10. 10.Best estimate of 1917 ÷ 81? (a) 240 (b) 24 (c) 2400
  11. 11.√40 to 1 decimal place? (a) 6.0 (b) 6.2 (c) 6.3 (d) 6.1
  12. 12.Best estimate of 1474 ÷ 29? (a) 49 (b) 4900 (c) 490
  13. 13.Best estimate of 423 ÷ 21? (a) 210 (b) 2100 (c) 21
  14. 14.√82 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.4
  15. 15.√90 to 1 decimal place? (a) 9.5 (b) 9.8 (c) 9.6 (d) 9.7
  16. 16.√37 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.0 (d) 6.2
  17. 17.Best estimate of 4945 ÷ 74? (a) 710 (b) 7100 (c) 71
  18. 18.√26 to 1 decimal place? (a) 5.2 (b) 5.4 (c) 5.1 (d) 5.3
  19. 19.√87 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.5
  20. 20.√27 to 1 decimal place? (a) 5.2 (b) 5.0 (c) 5.1 (d) 4.9
  21. 21.Best estimate of 1796 ÷ 38? (a) 45 (b) 4500 (c) 450
  22. 22.Best estimate of 1366 ÷ 63? (a) 230 (b) 2300 (c) 23
  23. 23.Best estimate of 8024 ÷ 86? (a) 8900 (b) 890 (c) 89
  24. 24.√38 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 6.2 (d) 6.3
  25. 25.√43 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.5 (d) 6.8
  26. 26.Best estimate of 3655 ÷ 46? (a) 730 (b) 7300 (c) 73
  27. 27.√83 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.2 (d) 9.4
  28. 28.Best estimate of 1404 ÷ 46? (a) 2800 (b) 28 (c) 280
  29. 29.Best estimate of 2553 ÷ 36? (a) 6400 (b) 640 (c) 64
  30. 30.Best estimate of 1566 ÷ 73? (a) 220 (b) 2200 (c) 22
  31. 31.Best estimate of 6016 ÷ 66? (a) 860 (b) 8600 (c) 86
  32. 32.Best estimate of 3466 ÷ 42? (a) 87 (b) 870 (c) 8700
  33. 33.Best estimate of 2887 ÷ 76? (a) 360 (b) 3600 (c) 36
  34. 34.Best estimate of 2225 ÷ 69? (a) 32 (b) 3200 (c) 320
  35. 35.Best estimate of 1061 ÷ 32? (a) 3500 (b) 350 (c) 35
  36. 36.Best estimate of 3572 ÷ 63? (a) 6000 (b) 600 (c) 60
  37. 37.Best estimate of 3262 ÷ 67? (a) 470 (b) 4700 (c) 47
  38. 38.√86 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.6 (d) 9.5
  39. 39.Best estimate of 6373 ÷ 72? (a) 91 (b) 9100 (c) 910
  40. 40.Best estimate of 2459 ÷ 27? (a) 82 (b) 820 (c) 8200

Answer key

  1. 8.3
  2. 102
  3. 36
  4. 91
  5. 12
  6. 4.7
  7. 9.6
  8. 14
  9. 64
  10. 24
  11. 6.3
  12. 49
  13. 21
  14. 9.1
  15. 9.5
  16. 6.1
  17. 71
  18. 5.1
  19. 9.3
  20. 5.2
  21. 45
  22. 23
  23. 89
  24. 6.2
  25. 6.6
  26. 73
  27. 9.1
  28. 28
  29. 64
  30. 22
  31. 86
  32. 87
  33. 36
  34. 32
  35. 35
  36. 60
  37. 47
  38. 9.3
  39. 91
  40. 82

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