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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 508 · 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 3928 ÷ 82? (a) 49 (b) 4900 (c) 490
  2. 2.Best estimate of 3764 ÷ 66? (a) 5400 (b) 540 (c) 54
  3. 3.Best estimate of 4851 ÷ 62? (a) 810 (b) 8100 (c) 81
  4. 4.Best estimate of 786 ÷ 26? (a) 26 (b) 2600 (c) 260
  5. 5.√82 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 9.2 (d) 8.9
  6. 6.Best estimate of 5860 ÷ 69? (a) 840 (b) 8400 (c) 84
  7. 7.Best estimate of 2266 ÷ 47? (a) 4500 (b) 450 (c) 45
  8. 8.Best estimate of 4182 ÷ 74? (a) 60 (b) 6000 (c) 600
  9. 9.Best estimate of 1180 ÷ 62? (a) 20 (b) 2000 (c) 200
  10. 10.Best estimate of 933 ÷ 27? (a) 310 (b) 3100 (c) 31
  11. 11.√72 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.4
  12. 12.√27 to 1 decimal place? (a) 5.3 (b) 5.2 (c) 5.1 (d) 5.0
  13. 13.Best estimate of 1249 ÷ 31? (a) 4200 (b) 420 (c) 42
  14. 14.√75 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.6 (d) 8.5
  15. 15.Best estimate of 3198 ÷ 62? (a) 53 (b) 530 (c) 5300
  16. 16.Best estimate of 1765 ÷ 27? (a) 590 (b) 59 (c) 5900
  17. 17.Best estimate of 2065 ÷ 22? (a) 10300 (b) 103 (c) 1030
  18. 18.Best estimate of 3569 ÷ 86? (a) 400 (b) 4000 (c) 40
  19. 19.Best estimate of 2823 ÷ 46? (a) 5600 (b) 560 (c) 56
  20. 20.Best estimate of 5863 ÷ 82? (a) 73 (b) 7300 (c) 730
  21. 21.Best estimate of 1302 ÷ 56? (a) 22 (b) 2200 (c) 220
  22. 22.√88 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.7 (d) 9.6
  23. 23.Best estimate of 1494 ÷ 26? (a) 500 (b) 5000 (c) 50
  24. 24.√44 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.8 (d) 6.5
  25. 25.√62 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 7.7 (d) 7.8
  26. 26.Best estimate of 2439 ÷ 36? (a) 61 (b) 610 (c) 6100
  27. 27.√42 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.7 (d) 6.8
  28. 28.Best estimate of 1088 ÷ 31? (a) 360 (b) 36 (c) 3600
  29. 29.√24 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 4.8 (d) 4.9
  30. 30.√89 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.5
  31. 31.√74 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  32. 32.Best estimate of 1868 ÷ 28? (a) 620 (b) 6200 (c) 62
  33. 33.Best estimate of 1774 ÷ 84? (a) 2200 (b) 220 (c) 22
  34. 34.Best estimate of 1233 ÷ 26? (a) 410 (b) 4100 (c) 41
  35. 35.√26 to 1 decimal place? (a) 4.9 (b) 4.8 (c) 5.0 (d) 5.1
  36. 36.Best estimate of 4009 ÷ 76? (a) 50 (b) 5000 (c) 500
  37. 37.Best estimate of 479 ÷ 26? (a) 160 (b) 1600 (c) 16
  38. 38.Best estimate of 1552 ÷ 43? (a) 39 (b) 3900 (c) 390
  39. 39.Best estimate of 2097 ÷ 27? (a) 70 (b) 700 (c) 7000
  40. 40.Best estimate of 2591 ÷ 62? (a) 4300 (b) 43 (c) 430

Answer key

  1. 49
  2. 54
  3. 81
  4. 26
  5. 9.1
  6. 84
  7. 45
  8. 60
  9. 20
  10. 31
  11. 8.5
  12. 5.2
  13. 42
  14. 8.7
  15. 53
  16. 59
  17. 103
  18. 40
  19. 56
  20. 73
  21. 22
  22. 9.4
  23. 50
  24. 6.6
  25. 7.9
  26. 61
  27. 6.5
  28. 36
  29. 4.9
  30. 9.4
  31. 8.6
  32. 62
  33. 22
  34. 41
  35. 5.1
  36. 50
  37. 16
  38. 39
  39. 70
  40. 43

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