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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 659 · 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 1043 ÷ 82? (a) 1300 (b) 13 (c) 130
  2. 2.Best estimate of 3328 ÷ 62? (a) 5500 (b) 550 (c) 55
  3. 3.Best estimate of 1059 ÷ 31? (a) 35 (b) 3500 (c) 350
  4. 4.√89 to 1 decimal place? (a) 9.7 (b) 9.4 (c) 9.6 (d) 9.5
  5. 5.√61 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 7.8 (d) 8.0
  6. 6.Best estimate of 3353 ÷ 53? (a) 6700 (b) 670 (c) 67
  7. 7.Best estimate of 3683 ÷ 58? (a) 610 (b) 6100 (c) 61
  8. 8.√72 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.8 (d) 8.5
  9. 9.Best estimate of 8084 ÷ 86? (a) 900 (b) 9000 (c) 90
  10. 10.Best estimate of 6218 ÷ 68? (a) 8900 (b) 89 (c) 890
  11. 11.Best estimate of 6232 ÷ 82? (a) 78 (b) 7800 (c) 780
  12. 12.Best estimate of 2258 ÷ 26? (a) 750 (b) 7500 (c) 75
  13. 13.√87 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.3 (d) 9.2
  14. 14.Best estimate of 481 ÷ 27? (a) 160 (b) 1600 (c) 16
  15. 15.Best estimate of 4430 ÷ 53? (a) 8900 (b) 890 (c) 89
  16. 16.√51 to 1 decimal place? (a) 6.9 (b) 7.2 (c) 7.0 (d) 7.1
  17. 17.Best estimate of 4332 ÷ 56? (a) 7200 (b) 72 (c) 720
  18. 18.√77 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  19. 19.Best estimate of 981 ÷ 28? (a) 330 (b) 33 (c) 3300
  20. 20.√44 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.4 (d) 6.7
  21. 21.Best estimate of 3110 ÷ 58? (a) 5200 (b) 52 (c) 520
  22. 22.√80 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 9.0 (d) 8.8
  23. 23.Best estimate of 1655 ÷ 84? (a) 2100 (b) 210 (c) 21
  24. 24.Best estimate of 3918 ÷ 68? (a) 5600 (b) 560 (c) 56
  25. 25.√52 to 1 decimal place? (a) 7.2 (b) 7.0 (c) 7.1 (d) 6.9
  26. 26.√96 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 9.7 (d) 9.6
  27. 27.Best estimate of 1069 ÷ 22? (a) 530 (b) 53 (c) 5300
  28. 28.Best estimate of 1653 ÷ 41? (a) 410 (b) 4100 (c) 41
  29. 29.Best estimate of 768 ÷ 36? (a) 19 (b) 1900 (c) 190
  30. 30.Best estimate of 1379 ÷ 46? (a) 280 (b) 2800 (c) 28
  31. 31.Best estimate of 3010 ÷ 53? (a) 6000 (b) 60 (c) 600
  32. 32.Best estimate of 2148 ÷ 81? (a) 270 (b) 27 (c) 2700
  33. 33.Best estimate of 2069 ÷ 32? (a) 690 (b) 6900 (c) 69
  34. 34.√69 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.0 (d) 8.1
  35. 35.√29 to 1 decimal place? (a) 5.4 (b) 5.2 (c) 5.5 (d) 5.3
  36. 36.Best estimate of 2188 ÷ 38? (a) 550 (b) 55 (c) 5500
  37. 37.√47 to 1 decimal place? (a) 6.6 (b) 6.9 (c) 6.7 (d) 6.8
  38. 38.Best estimate of 5556 ÷ 76? (a) 6900 (b) 69 (c) 690
  39. 39.Best estimate of 4217 ÷ 66? (a) 60 (b) 6000 (c) 600
  40. 40.Best estimate of 2462 ÷ 54? (a) 490 (b) 49 (c) 4900

Answer key

  1. 13
  2. 55
  3. 35
  4. 9.4
  5. 7.8
  6. 67
  7. 61
  8. 8.5
  9. 90
  10. 89
  11. 78
  12. 75
  13. 9.3
  14. 16
  15. 89
  16. 7.1
  17. 72
  18. 8.8
  19. 33
  20. 6.6
  21. 52
  22. 8.9
  23. 21
  24. 56
  25. 7.2
  26. 9.8
  27. 53
  28. 41
  29. 19
  30. 28
  31. 60
  32. 27
  33. 69
  34. 8.3
  35. 5.4
  36. 55
  37. 6.9
  38. 69
  39. 60
  40. 49

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