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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 997 · 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 5981 ÷ 67? (a) 850 (b) 8500 (c) 85
  2. 2.Best estimate of 1961 ÷ 63? (a) 330 (b) 3300 (c) 33
  3. 3.Best estimate of 3789 ÷ 42? (a) 9500 (b) 95 (c) 950
  4. 4.Best estimate of 639 ÷ 52? (a) 13 (b) 1300 (c) 130
  5. 5.Best estimate of 1010 ÷ 39? (a) 250 (b) 2500 (c) 25
  6. 6.Best estimate of 4314 ÷ 49? (a) 86 (b) 8600 (c) 860
  7. 7.Best estimate of 1000 ÷ 32? (a) 330 (b) 3300 (c) 33
  8. 8.√74 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.9 (d) 8.7
  9. 9.Best estimate of 686 ÷ 56? (a) 1100 (b) 110 (c) 11
  10. 10.Best estimate of 931 ÷ 27? (a) 310 (b) 3100 (c) 31
  11. 11.Best estimate of 685 ÷ 39? (a) 17 (b) 170 (c) 1700
  12. 12.√82 to 1 decimal place? (a) 8.9 (b) 9.1 (c) 8.8 (d) 9.0
  13. 13.Best estimate of 7816 ÷ 89? (a) 87 (b) 870 (c) 8700
  14. 14.√65 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.2 (d) 8.3
  15. 15.Best estimate of 1115 ÷ 24? (a) 5600 (b) 560 (c) 56
  16. 16.√67 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.2 (d) 8.5
  17. 17.√22 to 1 decimal place? (a) 4.8 (b) 4.7 (c) 4.5 (d) 4.6
  18. 18.√40 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  19. 19.√63 to 1 decimal place? (a) 7.9 (b) 7.6 (c) 7.7 (d) 7.8
  20. 20.√37 to 1 decimal place? (a) 6.3 (b) 6.0 (c) 6.2 (d) 6.1
  21. 21.Best estimate of 1157 ÷ 23? (a) 58 (b) 580 (c) 5800
  22. 22.Best estimate of 3459 ÷ 72? (a) 4900 (b) 490 (c) 49
  23. 23.Best estimate of 3894 ÷ 51? (a) 7800 (b) 780 (c) 78
  24. 24.√75 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.8 (d) 9.0
  25. 25.Best estimate of 5354 ÷ 89? (a) 5900 (b) 59 (c) 590
  26. 26.√24 to 1 decimal place? (a) 4.9 (b) 4.8 (c) 4.7 (d) 4.6
  27. 27.√53 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.3 (d) 7.0
  28. 28.√46 to 1 decimal place? (a) 6.8 (b) 7.0 (c) 6.9 (d) 7.1
  29. 29.√80 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 8.9 (d) 9.1
  30. 30.√20 to 1 decimal place? (a) 4.3 (b) 4.4 (c) 4.2 (d) 4.5
  31. 31.Best estimate of 1970 ÷ 27? (a) 6600 (b) 660 (c) 66
  32. 32.√89 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.2 (d) 9.1
  33. 33.√78 to 1 decimal place? (a) 8.9 (b) 9.1 (c) 8.8 (d) 9.0
  34. 34.√69 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.1 (d) 8.4
  35. 35.Best estimate of 1124 ÷ 36? (a) 2800 (b) 280 (c) 28
  36. 36.Best estimate of 4276 ÷ 52? (a) 860 (b) 8600 (c) 86
  37. 37.Best estimate of 650 ÷ 34? (a) 22 (b) 2200 (c) 220
  38. 38.Best estimate of 2147 ÷ 52? (a) 430 (b) 4300 (c) 43
  39. 39.Best estimate of 3104 ÷ 62? (a) 520 (b) 52 (c) 5200
  40. 40.Best estimate of 6270 ÷ 76? (a) 78 (b) 780 (c) 7800

Answer key

  1. 85
  2. 33
  3. 95
  4. 13
  5. 25
  6. 86
  7. 33
  8. 8.6
  9. 11
  10. 31
  11. 17
  12. 9.1
  13. 87
  14. 8.1
  15. 56
  16. 8.2
  17. 4.7
  18. 6.3
  19. 7.9
  20. 6.1
  21. 58
  22. 49
  23. 78
  24. 8.7
  25. 59
  26. 4.9
  27. 7.3
  28. 6.8
  29. 8.9
  30. 4.5
  31. 66
  32. 9.4
  33. 8.8
  34. 8.3
  35. 28
  36. 86
  37. 22
  38. 43
  39. 52
  40. 78

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