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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 899 · 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.√41 to 1 decimal place? (a) 6.2 (b) 6.5 (c) 6.3 (d) 6.4
  2. 2.Best estimate of 545 ÷ 34? (a) 180 (b) 1800 (c) 18
  3. 3.√32 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.6 (d) 5.4
  4. 4.Best estimate of 1351 ÷ 36? (a) 340 (b) 3400 (c) 34
  5. 5.Best estimate of 578 ÷ 27? (a) 1900 (b) 190 (c) 19
  6. 6.√27 to 1 decimal place? (a) 4.9 (b) 5.1 (c) 5.2 (d) 5.0
  7. 7.Best estimate of 3855 ÷ 46? (a) 77 (b) 770 (c) 7700
  8. 8.Best estimate of 3594 ÷ 57? (a) 6000 (b) 60 (c) 600
  9. 9.√62 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.8 (d) 7.9
  10. 10.√58 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.9 (d) 7.6
  11. 11.Best estimate of 3726 ÷ 52? (a) 75 (b) 7500 (c) 750
  12. 12.Best estimate of 2256 ÷ 52? (a) 4500 (b) 45 (c) 450
  13. 13.Best estimate of 1964 ÷ 39? (a) 490 (b) 49 (c) 4900
  14. 14.Best estimate of 6328 ÷ 83? (a) 790 (b) 79 (c) 7900
  15. 15.Best estimate of 2914 ÷ 41? (a) 730 (b) 7300 (c) 73
  16. 16.√26 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 5.2 (d) 4.9
  17. 17.Best estimate of 502 ÷ 28? (a) 170 (b) 17 (c) 1700
  18. 18.√37 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.2 (d) 6.1
  19. 19.Best estimate of 1384 ÷ 48? (a) 28 (b) 2800 (c) 280
  20. 20.Best estimate of 2335 ÷ 51? (a) 4700 (b) 470 (c) 47
  21. 21.Best estimate of 3254 ÷ 34? (a) 10800 (b) 108 (c) 1080
  22. 22.Best estimate of 1718 ÷ 78? (a) 2100 (b) 210 (c) 21
  23. 23.√71 to 1 decimal place? (a) 8.1 (b) 8.4 (c) 8.3 (d) 8.2
  24. 24.Best estimate of 392 ÷ 32? (a) 1300 (b) 13 (c) 130
  25. 25.√44 to 1 decimal place? (a) 6.6 (b) 6.9 (c) 6.8 (d) 6.7
  26. 26.Best estimate of 3467 ÷ 48? (a) 6900 (b) 690 (c) 69
  27. 27.Best estimate of 1011 ÷ 47? (a) 20 (b) 200 (c) 2000
  28. 28.√94 to 1 decimal place? (a) 9.7 (b) 9.9 (c) 10.0 (d) 9.8
  29. 29.Best estimate of 2884 ÷ 76? (a) 36 (b) 360 (c) 3600
  30. 30.√43 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.3 (d) 6.4
  31. 31.Best estimate of 4058 ÷ 72? (a) 580 (b) 58 (c) 5800
  32. 32.Best estimate of 1844 ÷ 48? (a) 3700 (b) 370 (c) 37
  33. 33.Best estimate of 395 ÷ 32? (a) 130 (b) 13 (c) 1300
  34. 34.√83 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 8.8 (d) 9.1
  35. 35.√98 to 1 decimal place? (a) 10.1 (b) 9.9 (c) 10.0 (d) 10.2
  36. 36.√34 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 5.7 (d) 5.8
  37. 37.Best estimate of 2096 ÷ 56? (a) 350 (b) 3500 (c) 35
  38. 38.Best estimate of 2558 ÷ 89? (a) 280 (b) 2800 (c) 28
  39. 39.√59 to 1 decimal place? (a) 7.6 (b) 7.8 (c) 7.7 (d) 7.9
  40. 40.Best estimate of 552 ÷ 24? (a) 280 (b) 2800 (c) 28

Answer key

  1. 6.4
  2. 18
  3. 5.7
  4. 34
  5. 19
  6. 5.2
  7. 77
  8. 60
  9. 7.9
  10. 7.6
  11. 75
  12. 45
  13. 49
  14. 79
  15. 73
  16. 5.1
  17. 17
  18. 6.1
  19. 28
  20. 47
  21. 108
  22. 21
  23. 8.4
  24. 13
  25. 6.6
  26. 69
  27. 20
  28. 9.7
  29. 36
  30. 6.6
  31. 58
  32. 37
  33. 13
  34. 9.1
  35. 9.9
  36. 5.8
  37. 35
  38. 28
  39. 7.7
  40. 28

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