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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 925 · 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.√50 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 7.2 (d) 6.9
  2. 2.Best estimate of 4707 ÷ 61? (a) 78 (b) 780 (c) 7800
  3. 3.√86 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.5 (d) 9.6
  4. 4.√35 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 6.2 (d) 5.9
  5. 5.Best estimate of 2259 ÷ 33? (a) 750 (b) 7500 (c) 75
  6. 6.Best estimate of 2021 ÷ 56? (a) 34 (b) 340 (c) 3400
  7. 7.√80 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.6 (d) 8.9
  8. 8.Best estimate of 897 ÷ 26? (a) 300 (b) 30 (c) 3000
  9. 9.Best estimate of 3016 ÷ 34? (a) 10100 (b) 1010 (c) 101
  10. 10.√77 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 8.7 (d) 9.0
  11. 11.Best estimate of 3126 ÷ 44? (a) 78 (b) 7800 (c) 780
  12. 12.Best estimate of 2162 ÷ 43? (a) 540 (b) 5400 (c) 54
  13. 13.√28 to 1 decimal place? (a) 5.4 (b) 5.2 (c) 5.3 (d) 5.5
  14. 14.Best estimate of 426 ÷ 21? (a) 2100 (b) 210 (c) 21
  15. 15.√26 to 1 decimal place? (a) 5.2 (b) 5.4 (c) 5.1 (d) 5.3
  16. 16.Best estimate of 704 ÷ 46? (a) 1400 (b) 140 (c) 14
  17. 17.Best estimate of 5483 ÷ 59? (a) 910 (b) 9100 (c) 91
  18. 18.√65 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 7.8 (d) 8.1
  19. 19.√32 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 5.7
  20. 20.√92 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.4 (d) 9.7
  21. 21.√40 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.4 (d) 6.2
  22. 22.Best estimate of 2855 ÷ 81? (a) 3600 (b) 36 (c) 360
  23. 23.√98 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 10.1 (d) 10.2
  24. 24.Best estimate of 654 ÷ 21? (a) 3300 (b) 330 (c) 33
  25. 25.√61 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.6 (d) 7.9
  26. 26.Best estimate of 6052 ÷ 71? (a) 8600 (b) 860 (c) 86
  27. 27.Best estimate of 2284 ÷ 77? (a) 290 (b) 29 (c) 2900
  28. 28.Best estimate of 2346 ÷ 72? (a) 340 (b) 3400 (c) 34
  29. 29.√37 to 1 decimal place? (a) 6.1 (b) 5.9 (c) 6.0 (d) 5.8
  30. 30.√31 to 1 decimal place? (a) 5.5 (b) 5.7 (c) 5.4 (d) 5.6
  31. 31.Best estimate of 1734 ÷ 72? (a) 250 (b) 2500 (c) 25
  32. 32.Best estimate of 1451 ÷ 77? (a) 18 (b) 180 (c) 1800
  33. 33.√94 to 1 decimal place? (a) 9.8 (b) 10.0 (c) 9.9 (d) 9.7
  34. 34.√41 to 1 decimal place? (a) 6.7 (b) 6.4 (c) 6.6 (d) 6.5
  35. 35.Best estimate of 1087 ÷ 26? (a) 360 (b) 36 (c) 3600
  36. 36.√38 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 5.9 (d) 6.0
  37. 37.Best estimate of 715 ÷ 24? (a) 3600 (b) 36 (c) 360
  38. 38.Best estimate of 1309 ÷ 32? (a) 44 (b) 4400 (c) 440
  39. 39.Best estimate of 1544 ÷ 52? (a) 3100 (b) 310 (c) 31
  40. 40.√69 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.6 (d) 8.3

Answer key

  1. 7.1
  2. 78
  3. 9.3
  4. 5.9
  5. 75
  6. 34
  7. 8.9
  8. 30
  9. 101
  10. 8.8
  11. 78
  12. 54
  13. 5.3
  14. 21
  15. 5.1
  16. 14
  17. 91
  18. 8.1
  19. 5.7
  20. 9.6
  21. 6.3
  22. 36
  23. 9.9
  24. 33
  25. 7.8
  26. 86
  27. 29
  28. 34
  29. 6.1
  30. 5.6
  31. 25
  32. 18
  33. 9.7
  34. 6.4
  35. 36
  36. 6.2
  37. 36
  38. 44
  39. 31
  40. 8.3

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