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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 977 · 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.√51 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.1 (d) 7.0
  2. 2.√26 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.1 (d) 5.4
  3. 3.√75 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.8 (d) 8.6
  4. 4.Best estimate of 1273 ÷ 67? (a) 180 (b) 1800 (c) 18
  5. 5.Best estimate of 1799 ÷ 38? (a) 4500 (b) 45 (c) 450
  6. 6.Best estimate of 2177 ÷ 52? (a) 4400 (b) 44 (c) 440
  7. 7.Best estimate of 3786 ÷ 62? (a) 6300 (b) 63 (c) 630
  8. 8.√47 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 6.6
  9. 9.√66 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.2 (d) 8.1
  10. 10.√94 to 1 decimal place? (a) 9.6 (b) 9.9 (c) 9.7 (d) 9.8
  11. 11.Best estimate of 4362 ÷ 46? (a) 870 (b) 8700 (c) 87
  12. 12.Best estimate of 1028 ÷ 22? (a) 510 (b) 51 (c) 5100
  13. 13.Best estimate of 1251 ÷ 44? (a) 3100 (b) 31 (c) 310
  14. 14.Best estimate of 5281 ÷ 57? (a) 880 (b) 88 (c) 8800
  15. 15.√96 to 1 decimal place? (a) 9.8 (b) 10.0 (c) 9.9 (d) 10.1
  16. 16.Best estimate of 3649 ÷ 48? (a) 730 (b) 73 (c) 7300
  17. 17.√79 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.9 (d) 8.7
  18. 18.Best estimate of 7816 ÷ 82? (a) 980 (b) 9800 (c) 98
  19. 19.√23 to 1 decimal place? (a) 4.8 (b) 4.7 (c) 4.9 (d) 4.6
  20. 20.Best estimate of 2712 ÷ 52? (a) 540 (b) 54 (c) 5400
  21. 21.√55 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.2 (d) 7.3
  22. 22.√58 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.7 (d) 7.8
  23. 23.Best estimate of 692 ÷ 42? (a) 1700 (b) 17 (c) 170
  24. 24.√40 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.2 (d) 6.5
  25. 25.√46 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.9 (d) 6.7
  26. 26.Best estimate of 8163 ÷ 86? (a) 910 (b) 9100 (c) 91
  27. 27.Best estimate of 2375 ÷ 36? (a) 590 (b) 59 (c) 5900
  28. 28.√21 to 1 decimal place? (a) 4.6 (b) 4.8 (c) 4.9 (d) 4.7
  29. 29.Best estimate of 3643 ÷ 52? (a) 730 (b) 73 (c) 7300
  30. 30.√37 to 1 decimal place? (a) 6.1 (b) 5.9 (c) 5.8 (d) 6.0
  31. 31.√62 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 8.0 (d) 7.9
  32. 32.Best estimate of 2820 ÷ 44? (a) 7100 (b) 71 (c) 710
  33. 33.√82 to 1 decimal place? (a) 9.3 (b) 9.0 (c) 9.2 (d) 9.1
  34. 34.√86 to 1 decimal place? (a) 9.3 (b) 9.6 (c) 9.4 (d) 9.5
  35. 35.Best estimate of 1607 ÷ 87? (a) 180 (b) 18 (c) 1800
  36. 36.√29 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.2 (d) 5.5
  37. 37.Best estimate of 1902 ÷ 56? (a) 32 (b) 3200 (c) 320
  38. 38.Best estimate of 4278 ÷ 84? (a) 530 (b) 5300 (c) 53
  39. 39.√98 to 1 decimal place? (a) 10.0 (b) 10.1 (c) 10.2 (d) 9.9
  40. 40.Best estimate of 804 ÷ 44? (a) 2000 (b) 20 (c) 200

Answer key

  1. 7.1
  2. 5.1
  3. 8.7
  4. 18
  5. 45
  6. 44
  7. 63
  8. 6.9
  9. 8.1
  10. 9.7
  11. 87
  12. 51
  13. 31
  14. 88
  15. 9.8
  16. 73
  17. 8.9
  18. 98
  19. 4.8
  20. 54
  21. 7.4
  22. 7.6
  23. 17
  24. 6.3
  25. 6.8
  26. 91
  27. 59
  28. 4.6
  29. 73
  30. 6.1
  31. 7.9
  32. 71
  33. 9.1
  34. 9.3
  35. 18
  36. 5.4
  37. 32
  38. 53
  39. 9.9
  40. 20

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