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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 493 · 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 4241 ÷ 89? (a) 47 (b) 470 (c) 4700
  2. 2.√63 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.9 (d) 7.8
  3. 3.√76 to 1 decimal place? (a) 8.8 (b) 8.9 (c) 8.7 (d) 9.0
  4. 4.Best estimate of 399 ÷ 21? (a) 200 (b) 2000 (c) 20
  5. 5.Best estimate of 1048 ÷ 56? (a) 1700 (b) 17 (c) 170
  6. 6.√45 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.8 (d) 6.5
  7. 7.Best estimate of 3003 ÷ 71? (a) 430 (b) 43 (c) 4300
  8. 8.Best estimate of 3199 ÷ 48? (a) 640 (b) 6400 (c) 64
  9. 9.Best estimate of 697 ÷ 24? (a) 35 (b) 3500 (c) 350
  10. 10.Best estimate of 657 ÷ 31? (a) 22 (b) 220 (c) 2200
  11. 11.√67 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 8.2 (d) 8.1
  12. 12.√40 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.3
  13. 13.Best estimate of 1206 ÷ 36? (a) 3000 (b) 30 (c) 300
  14. 14.Best estimate of 1664 ÷ 76? (a) 21 (b) 210 (c) 2100
  15. 15.√23 to 1 decimal place? (a) 4.8 (b) 5.0 (c) 5.1 (d) 4.9
  16. 16.Best estimate of 1556 ÷ 31? (a) 5200 (b) 520 (c) 52
  17. 17.√69 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.4 (d) 8.3
  18. 18.√24 to 1 decimal place? (a) 4.6 (b) 4.9 (c) 4.8 (d) 4.7
  19. 19.√44 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.9 (d) 6.6
  20. 20.√92 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.6 (d) 9.9
  21. 21.√41 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.7 (d) 6.5
  22. 22.√74 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.6 (d) 8.3
  23. 23.√34 to 1 decimal place? (a) 6.0 (b) 5.7 (c) 5.8 (d) 5.9
  24. 24.Best estimate of 1924 ÷ 68? (a) 270 (b) 2700 (c) 27
  25. 25.√78 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.6 (d) 8.5
  26. 26.√96 to 1 decimal place? (a) 10.1 (b) 9.9 (c) 10.0 (d) 9.8
  27. 27.√55 to 1 decimal place? (a) 7.5 (b) 7.3 (c) 7.4 (d) 7.6
  28. 28.Best estimate of 854 ÷ 32? (a) 28 (b) 280 (c) 2800
  29. 29.Best estimate of 1131 ÷ 36? (a) 2800 (b) 280 (c) 28
  30. 30.√62 to 1 decimal place? (a) 8.0 (b) 7.8 (c) 8.1 (d) 7.9
  31. 31.Best estimate of 4337 ÷ 46? (a) 8700 (b) 87 (c) 870
  32. 32.√87 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.4 (d) 9.2
  33. 33.Best estimate of 3989 ÷ 83? (a) 50 (b) 5000 (c) 500
  34. 34.√42 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.7 (d) 6.5
  35. 35.√86 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.1 (d) 9.2
  36. 36.Best estimate of 1329 ÷ 26? (a) 4400 (b) 440 (c) 44
  37. 37.√31 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.5 (d) 5.6
  38. 38.√98 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.9 (d) 10.0
  39. 39.Best estimate of 1107 ÷ 74? (a) 160 (b) 16 (c) 1600
  40. 40.√80 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 9.1 (d) 9.2

Answer key

  1. 47
  2. 7.9
  3. 8.7
  4. 20
  5. 17
  6. 6.7
  7. 43
  8. 64
  9. 35
  10. 22
  11. 8.2
  12. 6.3
  13. 30
  14. 21
  15. 4.8
  16. 52
  17. 8.3
  18. 4.9
  19. 6.6
  20. 9.6
  21. 6.4
  22. 8.6
  23. 5.8
  24. 27
  25. 8.8
  26. 9.8
  27. 7.4
  28. 28
  29. 28
  30. 7.9
  31. 87
  32. 9.3
  33. 50
  34. 6.5
  35. 9.3
  36. 44
  37. 5.6
  38. 9.9
  39. 16
  40. 8.9

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