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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 311 · 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 4802 ÷ 52? (a) 9600 (b) 96 (c) 960
  2. 2.Best estimate of 1447 ÷ 26? (a) 4800 (b) 480 (c) 48
  3. 3.√59 to 1 decimal place? (a) 8.0 (b) 7.8 (c) 7.9 (d) 7.7
  4. 4.Best estimate of 7909 ÷ 86? (a) 88 (b) 880 (c) 8800
  5. 5.Best estimate of 391 ÷ 22? (a) 200 (b) 20 (c) 2000
  6. 6.√89 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.3 (d) 9.2
  7. 7.√92 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.6 (d) 9.4
  8. 8.Best estimate of 741 ÷ 24? (a) 3700 (b) 370 (c) 37
  9. 9.Best estimate of 265 ÷ 22? (a) 13 (b) 1300 (c) 130
  10. 10.√61 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.5 (d) 7.6
  11. 11.√74 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.6 (d) 8.3
  12. 12.√20 to 1 decimal place? (a) 4.5 (b) 4.4 (c) 4.6 (d) 4.7
  13. 13.Best estimate of 2455 ÷ 41? (a) 610 (b) 6100 (c) 61
  14. 14.√34 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 5.6 (d) 5.8
  15. 15.Best estimate of 4052 ÷ 68? (a) 580 (b) 5800 (c) 58
  16. 16.Best estimate of 1195 ÷ 24? (a) 6000 (b) 600 (c) 60
  17. 17.Best estimate of 2349 ÷ 42? (a) 590 (b) 59 (c) 5900
  18. 18.√75 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.4 (d) 8.7
  19. 19.√96 to 1 decimal place? (a) 9.9 (b) 9.6 (c) 9.8 (d) 9.7
  20. 20.Best estimate of 1262 ÷ 76? (a) 1600 (b) 16 (c) 160
  21. 21.Best estimate of 6487 ÷ 83? (a) 810 (b) 81 (c) 8100
  22. 22.Best estimate of 2717 ÷ 56? (a) 450 (b) 4500 (c) 45
  23. 23.Best estimate of 5345 ÷ 72? (a) 760 (b) 76 (c) 7600
  24. 24.Best estimate of 2232 ÷ 28? (a) 7400 (b) 74 (c) 740
  25. 25.Best estimate of 2220 ÷ 27? (a) 74 (b) 740 (c) 7400
  26. 26.Best estimate of 6027 ÷ 69? (a) 8600 (b) 860 (c) 86
  27. 27.√94 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.9 (d) 9.6
  28. 28.Best estimate of 3416 ÷ 76? (a) 430 (b) 43 (c) 4300
  29. 29.Best estimate of 3263 ÷ 56? (a) 5400 (b) 54 (c) 540
  30. 30.√77 to 1 decimal place? (a) 8.8 (b) 9.0 (c) 8.9 (d) 8.7
  31. 31.Best estimate of 1234 ÷ 39? (a) 3100 (b) 310 (c) 31
  32. 32.Best estimate of 1961 ÷ 29? (a) 650 (b) 65 (c) 6500
  33. 33.Best estimate of 1087 ÷ 32? (a) 360 (b) 36 (c) 3600
  34. 34.√31 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 5.6 (d) 5.8
  35. 35.Best estimate of 6188 ÷ 76? (a) 7700 (b) 770 (c) 77
  36. 36.√83 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.1 (d) 9.2
  37. 37.Best estimate of 4470 ÷ 76? (a) 5600 (b) 560 (c) 56
  38. 38.√37 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 6.1 (d) 6.0
  39. 39.Best estimate of 2583 ÷ 49? (a) 5200 (b) 520 (c) 52
  40. 40.Best estimate of 1864 ÷ 31? (a) 62 (b) 6200 (c) 620

Answer key

  1. 96
  2. 48
  3. 7.7
  4. 88
  5. 20
  6. 9.4
  7. 9.6
  8. 37
  9. 13
  10. 7.8
  11. 8.6
  12. 4.5
  13. 61
  14. 5.8
  15. 58
  16. 60
  17. 59
  18. 8.7
  19. 9.8
  20. 16
  21. 81
  22. 45
  23. 76
  24. 74
  25. 74
  26. 86
  27. 9.7
  28. 43
  29. 54
  30. 8.8
  31. 31
  32. 65
  33. 36
  34. 5.6
  35. 77
  36. 9.1
  37. 56
  38. 6.1
  39. 52
  40. 62

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