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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 80 · 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.√55 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.4
  2. 2.√43 to 1 decimal place? (a) 6.9 (b) 6.7 (c) 6.6 (d) 6.8
  3. 3.Best estimate of 2973 ÷ 38? (a) 74 (b) 740 (c) 7400
  4. 4.√88 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.4 (d) 9.5
  5. 5.Best estimate of 886 ÷ 56? (a) 15 (b) 150 (c) 1500
  6. 6.Best estimate of 1816 ÷ 42? (a) 450 (b) 4500 (c) 45
  7. 7.√96 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.9 (d) 10.0
  8. 8.√62 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 7.8 (d) 7.7
  9. 9.√83 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 9.2 (d) 9.3
  10. 10.Best estimate of 4018 ÷ 76? (a) 500 (b) 50 (c) 5000
  11. 11.√41 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.2 (d) 6.3
  12. 12.Best estimate of 1539 ÷ 43? (a) 380 (b) 3800 (c) 38
  13. 13.√37 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 6.2 (d) 6.1
  14. 14.Best estimate of 3798 ÷ 44? (a) 950 (b) 95 (c) 9500
  15. 15.Best estimate of 1066 ÷ 76? (a) 130 (b) 1300 (c) 13
  16. 16.Best estimate of 4895 ÷ 76? (a) 610 (b) 6100 (c) 61
  17. 17.Best estimate of 1426 ÷ 33? (a) 4800 (b) 480 (c) 48
  18. 18.Best estimate of 2057 ÷ 29? (a) 69 (b) 690 (c) 6900
  19. 19.Best estimate of 984 ÷ 62? (a) 1600 (b) 16 (c) 160
  20. 20.Best estimate of 2819 ÷ 38? (a) 700 (b) 7000 (c) 70
  21. 21.Best estimate of 2307 ÷ 66? (a) 3300 (b) 33 (c) 330
  22. 22.Best estimate of 3893 ÷ 44? (a) 9700 (b) 97 (c) 970
  23. 23.Best estimate of 2300 ÷ 31? (a) 7700 (b) 77 (c) 770
  24. 24.Best estimate of 2639 ÷ 28? (a) 8800 (b) 88 (c) 880
  25. 25.√38 to 1 decimal place? (a) 6.3 (b) 6.0 (c) 6.2 (d) 6.1
  26. 26.Best estimate of 2284 ÷ 38? (a) 5700 (b) 57 (c) 570
  27. 27.Best estimate of 2148 ÷ 32? (a) 72 (b) 7200 (c) 720
  28. 28.Best estimate of 579 ÷ 29? (a) 19 (b) 1900 (c) 190
  29. 29.Best estimate of 2486 ÷ 63? (a) 4100 (b) 41 (c) 410
  30. 30.Best estimate of 7187 ÷ 82? (a) 9000 (b) 900 (c) 90
  31. 31.√21 to 1 decimal place? (a) 4.5 (b) 4.6 (c) 4.8 (d) 4.7
  32. 32.Best estimate of 4768 ÷ 54? (a) 95 (b) 950 (c) 9500
  33. 33.Best estimate of 2486 ÷ 42? (a) 62 (b) 620 (c) 6200
  34. 34.√44 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.4 (d) 6.6
  35. 35.Best estimate of 3372 ÷ 42? (a) 8400 (b) 84 (c) 840
  36. 36.Best estimate of 1928 ÷ 42? (a) 480 (b) 4800 (c) 48
  37. 37.Best estimate of 1252 ÷ 42? (a) 31 (b) 3100 (c) 310
  38. 38.√98 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.7 (d) 9.8
  39. 39.√63 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 7.8 (d) 8.1
  40. 40.Best estimate of 1289 ÷ 36? (a) 3200 (b) 320 (c) 32

Answer key

  1. 7.4
  2. 6.6
  3. 74
  4. 9.4
  5. 15
  6. 45
  7. 9.8
  8. 7.9
  9. 9.1
  10. 50
  11. 6.4
  12. 38
  13. 6.1
  14. 95
  15. 13
  16. 61
  17. 48
  18. 69
  19. 16
  20. 70
  21. 33
  22. 97
  23. 77
  24. 88
  25. 6.2
  26. 57
  27. 72
  28. 19
  29. 41
  30. 90
  31. 4.6
  32. 95
  33. 62
  34. 6.6
  35. 84
  36. 48
  37. 31
  38. 9.9
  39. 7.9
  40. 32

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