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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 456 · 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 4962 ÷ 53? (a) 990 (b) 9900 (c) 99
  2. 2.Best estimate of 2268 ÷ 73? (a) 32 (b) 320 (c) 3200
  3. 3.√24 to 1 decimal place? (a) 5.1 (b) 4.9 (c) 5.0 (d) 4.8
  4. 4.√37 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.3 (d) 6.4
  5. 5.√48 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.0 (d) 6.7
  6. 6.√87 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.3 (d) 9.2
  7. 7.√50 to 1 decimal place? (a) 7.0 (b) 7.2 (c) 6.9 (d) 7.1
  8. 8.√89 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.6 (d) 9.3
  9. 9.Best estimate of 2197 ÷ 46? (a) 4400 (b) 44 (c) 440
  10. 10.Best estimate of 790 ÷ 32? (a) 2600 (b) 260 (c) 26
  11. 11.√47 to 1 decimal place? (a) 6.8 (b) 7.0 (c) 6.7 (d) 6.9
  12. 12.Best estimate of 5501 ÷ 87? (a) 6100 (b) 61 (c) 610
  13. 13.√45 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.7 (d) 6.6
  14. 14.√82 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.3 (d) 9.0
  15. 15.Best estimate of 1296 ÷ 37? (a) 3200 (b) 32 (c) 320
  16. 16.Best estimate of 2118 ÷ 26? (a) 710 (b) 7100 (c) 71
  17. 17.√23 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 4.8 (d) 5.1
  18. 18.Best estimate of 2393 ÷ 62? (a) 40 (b) 400 (c) 4000
  19. 19.Best estimate of 1151 ÷ 79? (a) 14 (b) 140 (c) 1400
  20. 20.Best estimate of 1595 ÷ 67? (a) 2300 (b) 230 (c) 23
  21. 21.Best estimate of 1391 ÷ 33? (a) 4600 (b) 460 (c) 46
  22. 22.Best estimate of 504 ÷ 31? (a) 17 (b) 1700 (c) 170
  23. 23.Best estimate of 3382 ÷ 62? (a) 5600 (b) 56 (c) 560
  24. 24.√76 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.6 (d) 8.8
  25. 25.Best estimate of 5274 ÷ 67? (a) 750 (b) 7500 (c) 75
  26. 26.√65 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 7.9 (d) 8.1
  27. 27.√67 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.3 (d) 8.0
  28. 28.√46 to 1 decimal place? (a) 6.9 (b) 6.7 (c) 6.8 (d) 6.6
  29. 29.Best estimate of 2305 ÷ 42? (a) 5800 (b) 58 (c) 580
  30. 30.Best estimate of 3322 ÷ 37? (a) 830 (b) 83 (c) 8300
  31. 31.Best estimate of 1535 ÷ 29? (a) 51 (b) 510 (c) 5100
  32. 32.√56 to 1 decimal place? (a) 7.5 (b) 7.2 (c) 7.3 (d) 7.4
  33. 33.Best estimate of 3929 ÷ 86? (a) 4400 (b) 440 (c) 44
  34. 34.Best estimate of 1745 ÷ 58? (a) 290 (b) 2900 (c) 29
  35. 35.Best estimate of 3721 ÷ 63? (a) 620 (b) 6200 (c) 62
  36. 36.Best estimate of 1784 ÷ 66? (a) 2500 (b) 250 (c) 25
  37. 37.√26 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.3 (d) 5.0
  38. 38.√28 to 1 decimal place? (a) 5.1 (b) 5.4 (c) 5.3 (d) 5.2
  39. 39.Best estimate of 1155 ÷ 48? (a) 230 (b) 2300 (c) 23
  40. 40.Best estimate of 4735 ÷ 69? (a) 6800 (b) 680 (c) 68

Answer key

  1. 99
  2. 32
  3. 4.9
  4. 6.1
  5. 6.9
  6. 9.3
  7. 7.1
  8. 9.4
  9. 44
  10. 26
  11. 6.9
  12. 61
  13. 6.7
  14. 9.1
  15. 32
  16. 71
  17. 4.8
  18. 40
  19. 14
  20. 23
  21. 46
  22. 17
  23. 56
  24. 8.7
  25. 75
  26. 8.1
  27. 8.2
  28. 6.8
  29. 58
  30. 83
  31. 51
  32. 7.5
  33. 44
  34. 29
  35. 62
  36. 25
  37. 5.1
  38. 5.3
  39. 23
  40. 68

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