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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 672 · 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 4309 ÷ 54? (a) 8600 (b) 860 (c) 86
  2. 2.Best estimate of 4676 ÷ 52? (a) 9400 (b) 94 (c) 940
  3. 3.√48 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.9 (d) 6.6
  4. 4.√46 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 6.8 (d) 6.7
  5. 5.Best estimate of 1329 ÷ 74? (a) 1900 (b) 19 (c) 190
  6. 6.Best estimate of 1327 ÷ 26? (a) 440 (b) 44 (c) 4400
  7. 7.√40 to 1 decimal place? (a) 6.3 (b) 6.5 (c) 6.4 (d) 6.6
  8. 8.√72 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.6 (d) 8.7
  9. 9.√37 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.4 (d) 6.2
  10. 10.Best estimate of 1136 ÷ 66? (a) 160 (b) 16 (c) 1600
  11. 11.√79 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 8.8 (d) 9.0
  12. 12.√92 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.5 (d) 9.4
  13. 13.Best estimate of 4388 ÷ 83? (a) 5500 (b) 55 (c) 550
  14. 14.√77 to 1 decimal place? (a) 8.7 (b) 9.0 (c) 8.9 (d) 8.8
  15. 15.√63 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 7.9 (d) 7.7
  16. 16.Best estimate of 1161 ÷ 36? (a) 29 (b) 290 (c) 2900
  17. 17.Best estimate of 4350 ÷ 51? (a) 870 (b) 8700 (c) 87
  18. 18.Best estimate of 2005 ÷ 28? (a) 670 (b) 6700 (c) 67
  19. 19.√24 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 4.9 (d) 5.0
  20. 20.√41 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.7 (d) 6.6
  21. 21.Best estimate of 1953 ÷ 42? (a) 4900 (b) 49 (c) 490
  22. 22.Best estimate of 3073 ÷ 39? (a) 77 (b) 770 (c) 7700
  23. 23.√82 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.4 (d) 9.3
  24. 24.Best estimate of 4142 ÷ 46? (a) 83 (b) 830 (c) 8300
  25. 25.Best estimate of 4391 ÷ 84? (a) 5500 (b) 550 (c) 55
  26. 26.Best estimate of 1633 ÷ 52? (a) 3300 (b) 33 (c) 330
  27. 27.√69 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 8.3 (d) 8.2
  28. 28.Best estimate of 8034 ÷ 87? (a) 89 (b) 8900 (c) 890
  29. 29.Best estimate of 6553 ÷ 71? (a) 94 (b) 9400 (c) 940
  30. 30.√67 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 8.3 (d) 8.2
  31. 31.Best estimate of 1717 ÷ 77? (a) 210 (b) 2100 (c) 21
  32. 32.√26 to 1 decimal place? (a) 5.0 (b) 4.8 (c) 4.9 (d) 5.1
  33. 33.Best estimate of 1438 ÷ 69? (a) 21 (b) 210 (c) 2100
  34. 34.Best estimate of 2668 ÷ 71? (a) 38 (b) 3800 (c) 380
  35. 35.Best estimate of 3744 ÷ 44? (a) 9400 (b) 94 (c) 940
  36. 36.Best estimate of 1086 ÷ 52? (a) 220 (b) 2200 (c) 22
  37. 37.Best estimate of 6803 ÷ 72? (a) 97 (b) 9700 (c) 970
  38. 38.Best estimate of 4657 ÷ 62? (a) 7800 (b) 780 (c) 78
  39. 39.Best estimate of 1817 ÷ 29? (a) 61 (b) 6100 (c) 610
  40. 40.Best estimate of 4882 ÷ 52? (a) 980 (b) 98 (c) 9800

Answer key

  1. 86
  2. 94
  3. 6.9
  4. 6.8
  5. 19
  6. 44
  7. 6.3
  8. 8.5
  9. 6.1
  10. 16
  11. 8.9
  12. 9.6
  13. 55
  14. 8.8
  15. 7.9
  16. 29
  17. 87
  18. 67
  19. 4.9
  20. 6.4
  21. 49
  22. 77
  23. 9.1
  24. 83
  25. 55
  26. 33
  27. 8.3
  28. 89
  29. 94
  30. 8.2
  31. 21
  32. 5.1
  33. 21
  34. 38
  35. 94
  36. 22
  37. 97
  38. 78
  39. 61
  40. 98

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