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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 396 · 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.√24 to 1 decimal place? (a) 5.2 (b) 5.0 (c) 4.9 (d) 5.1
  2. 2.Best estimate of 3803 ÷ 82? (a) 4800 (b) 480 (c) 48
  3. 3.√27 to 1 decimal place? (a) 5.3 (b) 5.0 (c) 5.1 (d) 5.2
  4. 4.√65 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.1 (d) 7.8
  5. 5.√55 to 1 decimal place? (a) 7.4 (b) 7.2 (c) 7.1 (d) 7.3
  6. 6.√72 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.7 (d) 8.5
  7. 7.Best estimate of 5770 ÷ 69? (a) 82 (b) 8200 (c) 820
  8. 8.√67 to 1 decimal place? (a) 8.5 (b) 8.2 (c) 8.4 (d) 8.3
  9. 9.Best estimate of 2459 ÷ 89? (a) 270 (b) 2700 (c) 27
  10. 10.Best estimate of 1355 ÷ 86? (a) 1500 (b) 150 (c) 15
  11. 11.Best estimate of 5328 ÷ 56? (a) 8900 (b) 890 (c) 89
  12. 12.Best estimate of 2678 ÷ 72? (a) 3800 (b) 380 (c) 38
  13. 13.Best estimate of 3400 ÷ 36? (a) 850 (b) 8500 (c) 85
  14. 14.√37 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.4 (d) 6.2
  15. 15.√35 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 5.7 (d) 5.6
  16. 16.√82 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 9.1 (d) 8.8
  17. 17.Best estimate of 1602 ÷ 64? (a) 270 (b) 27 (c) 2700
  18. 18.Best estimate of 1649 ÷ 43? (a) 4100 (b) 410 (c) 41
  19. 19.√92 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.4 (d) 9.6
  20. 20.√38 to 1 decimal place? (a) 6.3 (b) 6.5 (c) 6.4 (d) 6.2
  21. 21.√58 to 1 decimal place? (a) 7.6 (b) 7.3 (c) 7.5 (d) 7.4
  22. 22.Best estimate of 3075 ÷ 56? (a) 51 (b) 510 (c) 5100
  23. 23.√51 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.0 (d) 7.3
  24. 24.Best estimate of 1007 ÷ 22? (a) 50 (b) 500 (c) 5000
  25. 25.Best estimate of 4333 ÷ 48? (a) 8700 (b) 87 (c) 870
  26. 26.Best estimate of 657 ÷ 36? (a) 160 (b) 16 (c) 1600
  27. 27.Best estimate of 2268 ÷ 68? (a) 320 (b) 32 (c) 3200
  28. 28.Best estimate of 2994 ÷ 57? (a) 5000 (b) 50 (c) 500
  29. 29.Best estimate of 1238 ÷ 36? (a) 31 (b) 3100 (c) 310
  30. 30.√22 to 1 decimal place? (a) 4.6 (b) 4.7 (c) 4.5 (d) 4.8
  31. 31.√48 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 6.9 (d) 6.8
  32. 32.Best estimate of 1679 ÷ 27? (a) 560 (b) 5600 (c) 56
  33. 33.Best estimate of 1768 ÷ 58? (a) 2900 (b) 29 (c) 290
  34. 34.√77 to 1 decimal place? (a) 8.9 (b) 9.1 (c) 8.8 (d) 9.0
  35. 35.Best estimate of 2265 ÷ 62? (a) 3800 (b) 38 (c) 380
  36. 36.Best estimate of 1909 ÷ 71? (a) 270 (b) 2700 (c) 27
  37. 37.√96 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.7 (d) 9.9
  38. 38.Best estimate of 1787 ÷ 31? (a) 600 (b) 6000 (c) 60
  39. 39.Best estimate of 6907 ÷ 73? (a) 9900 (b) 99 (c) 990
  40. 40.Best estimate of 3931 ÷ 86? (a) 440 (b) 4400 (c) 44

Answer key

  1. 4.9
  2. 48
  3. 5.2
  4. 8.1
  5. 7.4
  6. 8.5
  7. 82
  8. 8.2
  9. 27
  10. 15
  11. 89
  12. 38
  13. 85
  14. 6.1
  15. 5.9
  16. 9.1
  17. 27
  18. 41
  19. 9.6
  20. 6.2
  21. 7.6
  22. 51
  23. 7.1
  24. 50
  25. 87
  26. 16
  27. 32
  28. 50
  29. 31
  30. 4.7
  31. 6.9
  32. 56
  33. 29
  34. 8.8
  35. 38
  36. 27
  37. 9.8
  38. 60
  39. 99
  40. 44

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