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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 287 · 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.√53 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.2 (d) 7.3
  2. 2.Best estimate of 1934 ÷ 79? (a) 2400 (b) 24 (c) 240
  3. 3.Best estimate of 2160 ÷ 42? (a) 540 (b) 5400 (c) 54
  4. 4.√96 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.9 (d) 9.8
  5. 5.√94 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.9 (d) 10.0
  6. 6.√79 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 9.1 (d) 8.8
  7. 7.Best estimate of 2930 ÷ 68? (a) 420 (b) 4200 (c) 42
  8. 8.Best estimate of 4067 ÷ 66? (a) 5800 (b) 58 (c) 580
  9. 9.√24 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 4.9 (d) 5.0
  10. 10.√40 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.0 (d) 6.1
  11. 11.Best estimate of 841 ÷ 46? (a) 17 (b) 170 (c) 1700
  12. 12.Best estimate of 5308 ÷ 61? (a) 88 (b) 8800 (c) 880
  13. 13.Best estimate of 4386 ÷ 89? (a) 4900 (b) 490 (c) 49
  14. 14.√34 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 6.0 (d) 5.8
  15. 15.√58 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.4 (d) 7.6
  16. 16.√55 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.1 (d) 7.2
  17. 17.√59 to 1 decimal place? (a) 7.7 (b) 8.0 (c) 7.9 (d) 7.8
  18. 18.Best estimate of 2833 ÷ 33? (a) 940 (b) 94 (c) 9400
  19. 19.Best estimate of 1650 ÷ 58? (a) 2800 (b) 28 (c) 280
  20. 20.√70 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.4 (d) 8.5
  21. 21.Best estimate of 3922 ÷ 52? (a) 7800 (b) 780 (c) 78
  22. 22.Best estimate of 3604 ÷ 74? (a) 510 (b) 51 (c) 5100
  23. 23.Best estimate of 1885 ÷ 33? (a) 6300 (b) 630 (c) 63
  24. 24.√46 to 1 decimal place? (a) 6.5 (b) 6.8 (c) 6.7 (d) 6.6
  25. 25.Best estimate of 331 ÷ 27? (a) 110 (b) 11 (c) 1100
  26. 26.Best estimate of 3670 ÷ 82? (a) 460 (b) 4600 (c) 46
  27. 27.√89 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.2 (d) 9.4
  28. 28.Best estimate of 1363 ÷ 76? (a) 17 (b) 170 (c) 1700
  29. 29.Best estimate of 3430 ÷ 39? (a) 860 (b) 8600 (c) 86
  30. 30.Best estimate of 1000 ÷ 21? (a) 500 (b) 5000 (c) 50
  31. 31.Best estimate of 5027 ÷ 56? (a) 84 (b) 8400 (c) 840
  32. 32.Best estimate of 5509 ÷ 59? (a) 9200 (b) 92 (c) 920
  33. 33.√62 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 8.1 (d) 7.8
  34. 34.Best estimate of 961 ÷ 37? (a) 24 (b) 2400 (c) 240
  35. 35.√27 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.5 (d) 5.2
  36. 36.Best estimate of 574 ÷ 22? (a) 290 (b) 2900 (c) 29
  37. 37.√77 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.8 (d) 8.7
  38. 38.√66 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.3 (d) 8.0
  39. 39.√47 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.9 (d) 6.7
  40. 40.Best estimate of 2360 ÷ 43? (a) 590 (b) 5900 (c) 59

Answer key

  1. 7.3
  2. 24
  3. 54
  4. 9.8
  5. 9.7
  6. 8.9
  7. 42
  8. 58
  9. 4.9
  10. 6.3
  11. 17
  12. 88
  13. 49
  14. 5.8
  15. 7.6
  16. 7.4
  17. 7.7
  18. 94
  19. 28
  20. 8.4
  21. 78
  22. 51
  23. 63
  24. 6.8
  25. 11
  26. 46
  27. 9.4
  28. 17
  29. 86
  30. 50
  31. 84
  32. 92
  33. 7.9
  34. 24
  35. 5.2
  36. 29
  37. 8.8
  38. 8.1
  39. 6.9
  40. 59

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