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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 587 · 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 3604 ÷ 48? (a) 7200 (b) 72 (c) 720
  2. 2.Best estimate of 3042 ÷ 59? (a) 51 (b) 510 (c) 5100
  3. 3.√69 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 8.3 (d) 8.1
  4. 4.√32 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.4 (d) 5.7
  5. 5.√27 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.5 (d) 5.4
  6. 6.Best estimate of 3237 ÷ 52? (a) 6500 (b) 650 (c) 65
  7. 7.√24 to 1 decimal place? (a) 5.0 (b) 5.2 (c) 4.9 (d) 5.1
  8. 8.√75 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 9.0 (d) 8.8
  9. 9.Best estimate of 5843 ÷ 69? (a) 8300 (b) 830 (c) 83
  10. 10.Best estimate of 1683 ÷ 88? (a) 190 (b) 19 (c) 1900
  11. 11.√70 to 1 decimal place? (a) 8.5 (b) 8.3 (c) 8.6 (d) 8.4
  12. 12.Best estimate of 1893 ÷ 28? (a) 63 (b) 630 (c) 6300
  13. 13.√37 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.0 (d) 6.2
  14. 14.√58 to 1 decimal place? (a) 7.6 (b) 7.5 (c) 7.7 (d) 7.8
  15. 15.√62 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 7.7 (d) 7.8
  16. 16.Best estimate of 3582 ÷ 38? (a) 9000 (b) 900 (c) 90
  17. 17.Best estimate of 7626 ÷ 84? (a) 950 (b) 9500 (c) 95
  18. 18.√63 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 7.6 (d) 7.8
  19. 19.Best estimate of 2868 ÷ 41? (a) 72 (b) 720 (c) 7200
  20. 20.Best estimate of 1764 ÷ 41? (a) 4400 (b) 440 (c) 44
  21. 21.√89 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.6 (d) 9.7
  22. 22.Best estimate of 588 ÷ 43? (a) 15 (b) 1500 (c) 150
  23. 23.Best estimate of 1430 ÷ 27? (a) 48 (b) 4800 (c) 480
  24. 24.√53 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.3 (d) 7.2
  25. 25.Best estimate of 5344 ÷ 62? (a) 890 (b) 89 (c) 8900
  26. 26.Best estimate of 3483 ÷ 39? (a) 8700 (b) 870 (c) 87
  27. 27.√85 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.2 (d) 9.4
  28. 28.Best estimate of 557 ÷ 38? (a) 1400 (b) 140 (c) 14
  29. 29.Best estimate of 3922 ÷ 52? (a) 780 (b) 78 (c) 7800
  30. 30.√77 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 9.0 (d) 8.8
  31. 31.√74 to 1 decimal place? (a) 8.8 (b) 8.9 (c) 8.6 (d) 8.7
  32. 32.Best estimate of 2380 ÷ 71? (a) 340 (b) 3400 (c) 34
  33. 33.Best estimate of 1610 ÷ 26? (a) 540 (b) 5400 (c) 54
  34. 34.Best estimate of 1022 ÷ 59? (a) 170 (b) 1700 (c) 17
  35. 35.√65 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.3 (d) 8.4
  36. 36.√35 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 5.8 (d) 5.6
  37. 37.√41 to 1 decimal place? (a) 6.1 (b) 6.3 (c) 6.4 (d) 6.2
  38. 38.Best estimate of 1079 ÷ 47? (a) 2200 (b) 220 (c) 22
  39. 39.Best estimate of 3720 ÷ 46? (a) 7400 (b) 740 (c) 74
  40. 40.Best estimate of 1310 ÷ 79? (a) 16 (b) 1600 (c) 160

Answer key

  1. 72
  2. 51
  3. 8.3
  4. 5.7
  5. 5.2
  6. 65
  7. 4.9
  8. 8.7
  9. 83
  10. 19
  11. 8.4
  12. 63
  13. 6.1
  14. 7.6
  15. 7.9
  16. 90
  17. 95
  18. 7.9
  19. 72
  20. 44
  21. 9.4
  22. 15
  23. 48
  24. 7.3
  25. 89
  26. 87
  27. 9.2
  28. 14
  29. 78
  30. 8.8
  31. 8.6
  32. 34
  33. 54
  34. 17
  35. 8.1
  36. 5.9
  37. 6.4
  38. 22
  39. 74
  40. 16

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