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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 876 · 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 2010 ÷ 56? (a) 3400 (b) 340 (c) 34
  2. 2.Best estimate of 3344 ÷ 48? (a) 6700 (b) 670 (c) 67
  3. 3.√29 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.5 (d) 5.4
  4. 4.√46 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.7 (d) 6.8
  5. 5.Best estimate of 1394 ÷ 31? (a) 460 (b) 4600 (c) 46
  6. 6.Best estimate of 2430 ÷ 47? (a) 49 (b) 4900 (c) 490
  7. 7.Best estimate of 6156 ÷ 66? (a) 8800 (b) 88 (c) 880
  8. 8.√85 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.1 (d) 9.3
  9. 9.√71 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.3 (d) 8.4
  10. 10.√59 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 7.7 (d) 7.9
  11. 11.Best estimate of 1146 ÷ 37? (a) 290 (b) 29 (c) 2900
  12. 12.√86 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.6 (d) 9.3
  13. 13.√67 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.0 (d) 8.1
  14. 14.√42 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.5 (d) 6.2
  15. 15.√21 to 1 decimal place? (a) 4.6 (b) 4.4 (c) 4.3 (d) 4.5
  16. 16.Best estimate of 2656 ÷ 64? (a) 44 (b) 4400 (c) 440
  17. 17.Best estimate of 1137 ÷ 64? (a) 190 (b) 1900 (c) 19
  18. 18.√58 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.4 (d) 7.5
  19. 19.Best estimate of 2601 ÷ 82? (a) 3300 (b) 33 (c) 330
  20. 20.Best estimate of 2313 ÷ 33? (a) 7700 (b) 77 (c) 770
  21. 21.√47 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.0 (d) 7.1
  22. 22.√40 to 1 decimal place? (a) 6.2 (b) 6.5 (c) 6.4 (d) 6.3
  23. 23.√24 to 1 decimal place? (a) 5.0 (b) 4.8 (c) 4.9 (d) 5.1
  24. 24.√50 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.8 (d) 7.1
  25. 25.Best estimate of 971 ÷ 39? (a) 2400 (b) 240 (c) 24
  26. 26.Best estimate of 1421 ÷ 32? (a) 4700 (b) 470 (c) 47
  27. 27.Best estimate of 3619 ÷ 61? (a) 600 (b) 6000 (c) 60
  28. 28.Best estimate of 4464 ÷ 71? (a) 640 (b) 6400 (c) 64
  29. 29.Best estimate of 2266 ÷ 36? (a) 5700 (b) 570 (c) 57
  30. 30.√26 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 5.2 (d) 5.1
  31. 31.Best estimate of 1636 ÷ 72? (a) 23 (b) 230 (c) 2300
  32. 32.Best estimate of 1804 ÷ 28? (a) 6000 (b) 60 (c) 600
  33. 33.√55 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.3 (d) 7.2
  34. 34.Best estimate of 2217 ÷ 28? (a) 74 (b) 740 (c) 7400
  35. 35.√41 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.7 (d) 6.5
  36. 36.Best estimate of 1334 ÷ 52? (a) 27 (b) 270 (c) 2700
  37. 37.Best estimate of 1718 ÷ 84? (a) 210 (b) 2100 (c) 21
  38. 38.√94 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.5
  39. 39.Best estimate of 931 ÷ 31? (a) 3100 (b) 310 (c) 31
  40. 40.Best estimate of 2434 ÷ 26? (a) 81 (b) 8100 (c) 810

Answer key

  1. 34
  2. 67
  3. 5.4
  4. 6.8
  5. 46
  6. 49
  7. 88
  8. 9.2
  9. 8.4
  10. 7.7
  11. 29
  12. 9.3
  13. 8.2
  14. 6.5
  15. 4.6
  16. 44
  17. 19
  18. 7.6
  19. 33
  20. 77
  21. 6.9
  22. 6.3
  23. 4.9
  24. 7.1
  25. 24
  26. 47
  27. 60
  28. 64
  29. 57
  30. 5.1
  31. 23
  32. 60
  33. 7.4
  34. 74
  35. 6.4
  36. 27
  37. 21
  38. 9.7
  39. 31
  40. 81

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