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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 423 · 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 1955 ÷ 32? (a) 65 (b) 6500 (c) 650
  2. 2.√20 to 1 decimal place? (a) 4.8 (b) 4.5 (c) 4.6 (d) 4.7
  3. 3.Best estimate of 6621 ÷ 76? (a) 830 (b) 8300 (c) 83
  4. 4.√35 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 5.9
  5. 5.Best estimate of 2276 ÷ 39? (a) 57 (b) 5700 (c) 570
  6. 6.√63 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 8.2 (d) 7.9
  7. 7.Best estimate of 2390 ÷ 37? (a) 60 (b) 6000 (c) 600
  8. 8.Best estimate of 4180 ÷ 48? (a) 840 (b) 84 (c) 8400
  9. 9.√40 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.3 (d) 6.0
  10. 10.Best estimate of 3876 ÷ 87? (a) 430 (b) 4300 (c) 43
  11. 11.Best estimate of 4376 ÷ 81? (a) 550 (b) 55 (c) 5500
  12. 12.Best estimate of 783 ÷ 26? (a) 2600 (b) 260 (c) 26
  13. 13.Best estimate of 3695 ÷ 66? (a) 53 (b) 5300 (c) 530
  14. 14.Best estimate of 2347 ÷ 31? (a) 780 (b) 7800 (c) 78
  15. 15.Best estimate of 3763 ÷ 84? (a) 4700 (b) 47 (c) 470
  16. 16.Best estimate of 1337 ÷ 87? (a) 1500 (b) 15 (c) 150
  17. 17.√37 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 5.9
  18. 18.Best estimate of 3170 ÷ 77? (a) 4000 (b) 40 (c) 400
  19. 19.√30 to 1 decimal place? (a) 5.3 (b) 5.6 (c) 5.5 (d) 5.4
  20. 20.Best estimate of 2411 ÷ 26? (a) 800 (b) 8000 (c) 80
  21. 21.Best estimate of 1466 ÷ 23? (a) 730 (b) 7300 (c) 73
  22. 22.Best estimate of 1475 ÷ 59? (a) 2500 (b) 250 (c) 25
  23. 23.√92 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.3 (d) 9.5
  24. 24.Best estimate of 1094 ÷ 32? (a) 360 (b) 3600 (c) 36
  25. 25.Best estimate of 2767 ÷ 46? (a) 5500 (b) 550 (c) 55
  26. 26.Best estimate of 1008 ÷ 74? (a) 1400 (b) 14 (c) 140
  27. 27.√70 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.3 (d) 8.2
  28. 28.Best estimate of 842 ÷ 31? (a) 280 (b) 28 (c) 2800
  29. 29.Best estimate of 5606 ÷ 62? (a) 9300 (b) 93 (c) 930
  30. 30.√27 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.2 (d) 5.3
  31. 31.√34 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 6.1 (d) 5.8
  32. 32.√50 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.4 (d) 7.3
  33. 33.Best estimate of 1033 ÷ 32? (a) 3400 (b) 340 (c) 34
  34. 34.√26 to 1 decimal place? (a) 4.9 (b) 5.2 (c) 5.1 (d) 5.0
  35. 35.Best estimate of 4880 ÷ 58? (a) 810 (b) 81 (c) 8100
  36. 36.Best estimate of 2862 ÷ 84? (a) 360 (b) 36 (c) 3600
  37. 37.Best estimate of 4911 ÷ 58? (a) 82 (b) 8200 (c) 820
  38. 38.√98 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 10.0 (d) 9.7
  39. 39.Best estimate of 1528 ÷ 49? (a) 31 (b) 310 (c) 3100
  40. 40.Best estimate of 1486 ÷ 57? (a) 25 (b) 2500 (c) 250

Answer key

  1. 65
  2. 4.5
  3. 83
  4. 5.9
  5. 57
  6. 7.9
  7. 60
  8. 84
  9. 6.3
  10. 43
  11. 55
  12. 26
  13. 53
  14. 78
  15. 47
  16. 15
  17. 6.1
  18. 40
  19. 5.5
  20. 80
  21. 73
  22. 25
  23. 9.6
  24. 36
  25. 55
  26. 14
  27. 8.4
  28. 28
  29. 93
  30. 5.2
  31. 5.8
  32. 7.1
  33. 34
  34. 5.1
  35. 81
  36. 36
  37. 82
  38. 9.9
  39. 31
  40. 25

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