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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 562 · 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 2270 ÷ 29? (a) 760 (b) 76 (c) 7600
  2. 2.Best estimate of 2040 ÷ 46? (a) 41 (b) 410 (c) 4100
  3. 3.Best estimate of 1380 ÷ 58? (a) 230 (b) 2300 (c) 23
  4. 4.Best estimate of 4924 ÷ 76? (a) 62 (b) 620 (c) 6200
  5. 5.Best estimate of 1078 ÷ 66? (a) 1500 (b) 150 (c) 15
  6. 6.Best estimate of 3204 ÷ 37? (a) 800 (b) 80 (c) 8000
  7. 7.√67 to 1 decimal place? (a) 8.2 (b) 8.4 (c) 8.1 (d) 8.3
  8. 8.Best estimate of 639 ÷ 32? (a) 2100 (b) 21 (c) 210
  9. 9.√37 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.1 (d) 6.2
  10. 10.√50 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 6.9 (d) 7.0
  11. 11.√78 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.9 (d) 8.7
  12. 12.Best estimate of 3135 ÷ 44? (a) 780 (b) 78 (c) 7800
  13. 13.Best estimate of 2006 ÷ 46? (a) 400 (b) 4000 (c) 40
  14. 14.Best estimate of 7189 ÷ 82? (a) 90 (b) 900 (c) 9000
  15. 15.Best estimate of 1355 ÷ 26? (a) 45 (b) 4500 (c) 450
  16. 16.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 8.0 (d) 7.7
  17. 17.Best estimate of 393 ÷ 29? (a) 130 (b) 13 (c) 1300
  18. 18.Best estimate of 2255 ÷ 27? (a) 7500 (b) 750 (c) 75
  19. 19.√46 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.8 (d) 6.7
  20. 20.√82 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 9.0 (d) 8.8
  21. 21.Best estimate of 2472 ÷ 88? (a) 27 (b) 2700 (c) 270
  22. 22.Best estimate of 692 ÷ 32? (a) 230 (b) 23 (c) 2300
  23. 23.Best estimate of 2143 ÷ 82? (a) 270 (b) 2700 (c) 27
  24. 24.Best estimate of 3744 ÷ 72? (a) 530 (b) 5300 (c) 53
  25. 25.√38 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 6.2 (d) 6.3
  26. 26.Best estimate of 6391 ÷ 79? (a) 80 (b) 8000 (c) 800
  27. 27.Best estimate of 5041 ÷ 84? (a) 6300 (b) 630 (c) 63
  28. 28.Best estimate of 3771 ÷ 58? (a) 6300 (b) 63 (c) 630
  29. 29.Best estimate of 1519 ÷ 36? (a) 38 (b) 380 (c) 3800
  30. 30.Best estimate of 1360 ÷ 52? (a) 270 (b) 2700 (c) 27
  31. 31.Best estimate of 4051 ÷ 77? (a) 510 (b) 5100 (c) 51
  32. 32.Best estimate of 1910 ÷ 81? (a) 2400 (b) 24 (c) 240
  33. 33.Best estimate of 1212 ÷ 64? (a) 2000 (b) 200 (c) 20
  34. 34.√52 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.5 (d) 7.4
  35. 35.Best estimate of 2143 ÷ 34? (a) 710 (b) 71 (c) 7100
  36. 36.Best estimate of 5435 ÷ 62? (a) 9100 (b) 910 (c) 91
  37. 37.√62 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 7.9 (d) 8.1
  38. 38.Best estimate of 5987 ÷ 86? (a) 6700 (b) 670 (c) 67
  39. 39.√80 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 8.9 (d) 9.0
  40. 40.Best estimate of 6437 ÷ 82? (a) 8000 (b) 800 (c) 80

Answer key

  1. 76
  2. 41
  3. 23
  4. 62
  5. 15
  6. 80
  7. 8.2
  8. 21
  9. 6.1
  10. 7.1
  11. 8.8
  12. 78
  13. 40
  14. 90
  15. 45
  16. 7.8
  17. 13
  18. 75
  19. 6.8
  20. 9.1
  21. 27
  22. 23
  23. 27
  24. 53
  25. 6.2
  26. 80
  27. 63
  28. 63
  29. 38
  30. 27
  31. 51
  32. 24
  33. 20
  34. 7.2
  35. 71
  36. 91
  37. 7.9
  38. 67
  39. 8.9
  40. 80

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