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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 737 · 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 2452 ÷ 84? (a) 310 (b) 31 (c) 3100
  2. 2.Best estimate of 2309 ÷ 54? (a) 46 (b) 460 (c) 4600
  3. 3.Best estimate of 948 ÷ 33? (a) 32 (b) 320 (c) 3200
  4. 4.Best estimate of 2008 ÷ 58? (a) 330 (b) 33 (c) 3300
  5. 5.Best estimate of 4871 ÷ 72? (a) 7000 (b) 70 (c) 700
  6. 6.√65 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.2 (d) 8.3
  7. 7.Best estimate of 5079 ÷ 62? (a) 850 (b) 8500 (c) 85
  8. 8.Best estimate of 5273 ÷ 56? (a) 880 (b) 88 (c) 8800
  9. 9.√32 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 5.7
  10. 10.√69 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 8.2 (d) 8.3
  11. 11.√30 to 1 decimal place? (a) 5.3 (b) 5.2 (c) 5.5 (d) 5.4
  12. 12.√76 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 9.0 (d) 8.7
  13. 13.√94 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.4 (d) 9.7
  14. 14.Best estimate of 2468 ÷ 51? (a) 49 (b) 490 (c) 4900
  15. 15.Best estimate of 2932 ÷ 88? (a) 330 (b) 3300 (c) 33
  16. 16.√67 to 1 decimal place? (a) 7.9 (b) 8.2 (c) 8.1 (d) 8.0
  17. 17.Best estimate of 3427 ÷ 49? (a) 6900 (b) 690 (c) 69
  18. 18.Best estimate of 4927 ÷ 82? (a) 6200 (b) 62 (c) 620
  19. 19.Best estimate of 4806 ÷ 52? (a) 960 (b) 9600 (c) 96
  20. 20.√77 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.7 (d) 8.8
  21. 21.Best estimate of 1910 ÷ 72? (a) 27 (b) 2700 (c) 270
  22. 22.Best estimate of 4584 ÷ 54? (a) 9200 (b) 92 (c) 920
  23. 23.√56 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.4 (d) 7.6
  24. 24.Best estimate of 6449 ÷ 76? (a) 810 (b) 8100 (c) 81
  25. 25.√58 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 7.6
  26. 26.√41 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.5 (d) 6.4
  27. 27.Best estimate of 5649 ÷ 77? (a) 710 (b) 7100 (c) 71
  28. 28.√88 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.4 (d) 9.7
  29. 29.√61 to 1 decimal place? (a) 8.1 (b) 7.8 (c) 8.0 (d) 7.9
  30. 30.Best estimate of 1367 ÷ 48? (a) 2700 (b) 270 (c) 27
  31. 31.Best estimate of 1435 ÷ 24? (a) 720 (b) 7200 (c) 72
  32. 32.Best estimate of 1771 ÷ 39? (a) 4400 (b) 440 (c) 44
  33. 33.Best estimate of 538 ÷ 44? (a) 13 (b) 1300 (c) 130
  34. 34.Best estimate of 1115 ÷ 22? (a) 560 (b) 56 (c) 5600
  35. 35.√74 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.6 (d) 8.5
  36. 36.Best estimate of 940 ÷ 69? (a) 13 (b) 1300 (c) 130
  37. 37.Best estimate of 3822 ÷ 51? (a) 760 (b) 76 (c) 7600
  38. 38.√90 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.4
  39. 39.Best estimate of 1394 ÷ 46? (a) 28 (b) 2800 (c) 280
  40. 40.√53 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 7.2 (d) 7.3

Answer key

  1. 31
  2. 46
  3. 32
  4. 33
  5. 70
  6. 8.1
  7. 85
  8. 88
  9. 5.7
  10. 8.3
  11. 5.5
  12. 8.7
  13. 9.7
  14. 49
  15. 33
  16. 8.2
  17. 69
  18. 62
  19. 96
  20. 8.8
  21. 27
  22. 92
  23. 7.5
  24. 81
  25. 7.6
  26. 6.4
  27. 71
  28. 9.4
  29. 7.8
  30. 27
  31. 72
  32. 44
  33. 13
  34. 56
  35. 8.6
  36. 13
  37. 76
  38. 9.5
  39. 28
  40. 7.3

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