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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 48 · 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 3244 ÷ 47? (a) 6500 (b) 65 (c) 650
  2. 2.Best estimate of 777 ÷ 42? (a) 190 (b) 1900 (c) 19
  3. 3.√88 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.6 (d) 9.5
  4. 4.Best estimate of 5552 ÷ 63? (a) 930 (b) 93 (c) 9300
  5. 5.√71 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.4 (d) 8.7
  6. 6.Best estimate of 2248 ÷ 36? (a) 5600 (b) 560 (c) 56
  7. 7.Best estimate of 4166 ÷ 82? (a) 5200 (b) 52 (c) 520
  8. 8.Best estimate of 965 ÷ 36? (a) 2400 (b) 24 (c) 240
  9. 9.Best estimate of 595 ÷ 32? (a) 20 (b) 2000 (c) 200
  10. 10.Best estimate of 3540 ÷ 72? (a) 510 (b) 51 (c) 5100
  11. 11.√52 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.4 (d) 7.3
  12. 12.√46 to 1 decimal place? (a) 6.9 (b) 7.1 (c) 6.8 (d) 7.0
  13. 13.Best estimate of 1756 ÷ 56? (a) 290 (b) 29 (c) 2900
  14. 14.Best estimate of 5051 ÷ 54? (a) 101 (b) 1010 (c) 10100
  15. 15.Best estimate of 1809 ÷ 42? (a) 4500 (b) 45 (c) 450
  16. 16.Best estimate of 1907 ÷ 21? (a) 95 (b) 9500 (c) 950
  17. 17.√98 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.9
  18. 18.Best estimate of 1009 ÷ 62? (a) 170 (b) 1700 (c) 17
  19. 19.Best estimate of 3616 ÷ 48? (a) 72 (b) 720 (c) 7200
  20. 20.Best estimate of 5119 ÷ 83? (a) 640 (b) 6400 (c) 64
  21. 21.Best estimate of 662 ÷ 36? (a) 170 (b) 1700 (c) 17
  22. 22.Best estimate of 1018 ÷ 32? (a) 34 (b) 340 (c) 3400
  23. 23.√20 to 1 decimal place? (a) 4.6 (b) 4.5 (c) 4.4 (d) 4.7
  24. 24.√40 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.4 (d) 6.3
  25. 25.Best estimate of 4134 ÷ 59? (a) 6900 (b) 690 (c) 69
  26. 26.Best estimate of 3353 ÷ 37? (a) 840 (b) 84 (c) 8400
  27. 27.Best estimate of 2241 ÷ 62? (a) 37 (b) 370 (c) 3700
  28. 28.Best estimate of 1673 ÷ 77? (a) 210 (b) 21 (c) 2100
  29. 29.Best estimate of 1016 ÷ 46? (a) 2000 (b) 20 (c) 200
  30. 30.√48 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 6.7 (d) 6.8
  31. 31.Best estimate of 3357 ÷ 36? (a) 840 (b) 8400 (c) 84
  32. 32.Best estimate of 646 ÷ 29? (a) 22 (b) 2200 (c) 220
  33. 33.√87 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.5
  34. 34.Best estimate of 6050 ÷ 72? (a) 86 (b) 8600 (c) 860
  35. 35.√96 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.9 (d) 9.6
  36. 36.Best estimate of 2380 ÷ 72? (a) 34 (b) 340 (c) 3400
  37. 37.√61 to 1 decimal place? (a) 7.6 (b) 7.8 (c) 7.7 (d) 7.5
  38. 38.Best estimate of 1916 ÷ 32? (a) 640 (b) 6400 (c) 64
  39. 39.√26 to 1 decimal place? (a) 5.4 (b) 5.2 (c) 5.3 (d) 5.1
  40. 40.Best estimate of 4943 ÷ 68? (a) 710 (b) 71 (c) 7100

Answer key

  1. 65
  2. 19
  3. 9.4
  4. 93
  5. 8.4
  6. 56
  7. 52
  8. 24
  9. 20
  10. 51
  11. 7.2
  12. 6.8
  13. 29
  14. 101
  15. 45
  16. 95
  17. 9.9
  18. 17
  19. 72
  20. 64
  21. 17
  22. 34
  23. 4.5
  24. 6.3
  25. 69
  26. 84
  27. 37
  28. 21
  29. 20
  30. 6.9
  31. 84
  32. 22
  33. 9.3
  34. 86
  35. 9.8
  36. 34
  37. 7.8
  38. 64
  39. 5.1
  40. 71

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