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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 334 · 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 3375 ÷ 66? (a) 4800 (b) 48 (c) 480
  2. 2.Best estimate of 3799 ÷ 66? (a) 54 (b) 5400 (c) 540
  3. 3.Best estimate of 795 ÷ 42? (a) 2000 (b) 20 (c) 200
  4. 4.√86 to 1 decimal place? (a) 9.1 (b) 9.4 (c) 9.3 (d) 9.2
  5. 5.Best estimate of 1117 ÷ 33? (a) 3700 (b) 370 (c) 37
  6. 6.Best estimate of 696 ÷ 28? (a) 2300 (b) 230 (c) 23
  7. 7.√85 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 9.2 (d) 9.0
  8. 8.Best estimate of 854 ÷ 27? (a) 280 (b) 28 (c) 2800
  9. 9.Best estimate of 1226 ÷ 32? (a) 4100 (b) 410 (c) 41
  10. 10.√38 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 6.3
  11. 11.Best estimate of 2176 ÷ 44? (a) 540 (b) 5400 (c) 54
  12. 12.Best estimate of 1531 ÷ 29? (a) 5100 (b) 51 (c) 510
  13. 13.√31 to 1 decimal place? (a) 5.5 (b) 5.8 (c) 5.6 (d) 5.7
  14. 14.√45 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.9 (d) 6.7
  15. 15.Best estimate of 1978 ÷ 32? (a) 6600 (b) 66 (c) 660
  16. 16.√84 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.0 (d) 8.9
  17. 17.√34 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 5.9 (d) 5.8
  18. 18.Best estimate of 2519 ÷ 77? (a) 31 (b) 310 (c) 3100
  19. 19.Best estimate of 4009 ÷ 76? (a) 5000 (b) 50 (c) 500
  20. 20.Best estimate of 869 ÷ 28? (a) 290 (b) 2900 (c) 29
  21. 21.√30 to 1 decimal place? (a) 5.8 (b) 5.6 (c) 5.5 (d) 5.7
  22. 22.√41 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  23. 23.√47 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 6.8 (d) 6.7
  24. 24.Best estimate of 1208 ÷ 68? (a) 170 (b) 1700 (c) 17
  25. 25.√59 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 7.8 (d) 8.0
  26. 26.√32 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.7 (d) 5.6
  27. 27.√40 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.3 (d) 6.6
  28. 28.Best estimate of 1396 ÷ 23? (a) 700 (b) 70 (c) 7000
  29. 29.√50 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 7.1 (d) 7.2
  30. 30.√20 to 1 decimal place? (a) 4.4 (b) 4.2 (c) 4.5 (d) 4.3
  31. 31.Best estimate of 5985 ÷ 83? (a) 750 (b) 75 (c) 7500
  32. 32.√44 to 1 decimal place? (a) 6.7 (b) 6.4 (c) 6.5 (d) 6.6
  33. 33.Best estimate of 3743 ÷ 64? (a) 620 (b) 62 (c) 6200
  34. 34.Best estimate of 3155 ÷ 62? (a) 530 (b) 53 (c) 5300
  35. 35.√26 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.1 (d) 5.2
  36. 36.Best estimate of 881 ÷ 28? (a) 290 (b) 29 (c) 2900
  37. 37.Best estimate of 3372 ÷ 81? (a) 4200 (b) 420 (c) 42
  38. 38.Best estimate of 2120 ÷ 23? (a) 10600 (b) 1060 (c) 106
  39. 39.√96 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 9.8 (d) 9.6
  40. 40.Best estimate of 1141 ÷ 82? (a) 1400 (b) 14 (c) 140

Answer key

  1. 48
  2. 54
  3. 20
  4. 9.3
  5. 37
  6. 23
  7. 9.2
  8. 28
  9. 41
  10. 6.2
  11. 54
  12. 51
  13. 5.6
  14. 6.7
  15. 66
  16. 9.2
  17. 5.8
  18. 31
  19. 50
  20. 29
  21. 5.5
  22. 6.4
  23. 6.9
  24. 17
  25. 7.7
  26. 5.7
  27. 6.3
  28. 70
  29. 7.1
  30. 4.5
  31. 75
  32. 6.6
  33. 62
  34. 53
  35. 5.1
  36. 29
  37. 42
  38. 106
  39. 9.8
  40. 14

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