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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 203 · 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 3217 ÷ 78? (a) 40 (b) 4000 (c) 400
  2. 2.Best estimate of 3551 ÷ 54? (a) 71 (b) 7100 (c) 710
  3. 3.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.0 (d) 8.9
  4. 4.Best estimate of 7274 ÷ 79? (a) 91 (b) 9100 (c) 910
  5. 5.Best estimate of 4628 ÷ 69? (a) 6600 (b) 66 (c) 660
  6. 6.Best estimate of 5636 ÷ 67? (a) 8100 (b) 81 (c) 810
  7. 7.√47 to 1 decimal place? (a) 6.6 (b) 6.9 (c) 6.8 (d) 6.7
  8. 8.Best estimate of 1657 ÷ 52? (a) 330 (b) 3300 (c) 33
  9. 9.Best estimate of 2301 ÷ 88? (a) 260 (b) 2600 (c) 26
  10. 10.√70 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.1 (d) 8.2
  11. 11.√53 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.2 (d) 7.3
  12. 12.Best estimate of 5068 ÷ 86? (a) 5600 (b) 560 (c) 56
  13. 13.Best estimate of 2204 ÷ 58? (a) 3700 (b) 37 (c) 370
  14. 14.√38 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 5.9 (d) 6.2
  15. 15.Best estimate of 629 ÷ 23? (a) 3100 (b) 310 (c) 31
  16. 16.Best estimate of 1262 ÷ 24? (a) 63 (b) 630 (c) 6300
  17. 17.Best estimate of 1310 ÷ 39? (a) 3300 (b) 33 (c) 330
  18. 18.Best estimate of 1965 ÷ 37? (a) 49 (b) 490 (c) 4900
  19. 19.√69 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.3 (d) 8.2
  20. 20.Best estimate of 2562 ÷ 89? (a) 280 (b) 2800 (c) 28
  21. 21.Best estimate of 818 ÷ 22? (a) 41 (b) 410 (c) 4100
  22. 22.√84 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.1
  23. 23.√37 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.3 (d) 6.4
  24. 24.Best estimate of 8021 ÷ 89? (a) 890 (b) 8900 (c) 89
  25. 25.Best estimate of 4729 ÷ 81? (a) 5900 (b) 59 (c) 590
  26. 26.Best estimate of 3006 ÷ 32? (a) 100 (b) 1000 (c) 10000
  27. 27.√22 to 1 decimal place? (a) 4.7 (b) 4.4 (c) 4.5 (d) 4.6
  28. 28.√62 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 7.8 (d) 8.1
  29. 29.Best estimate of 6840 ÷ 76? (a) 86 (b) 8600 (c) 860
  30. 30.√35 to 1 decimal place? (a) 6.1 (b) 5.8 (c) 6.0 (d) 5.9
  31. 31.√96 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.9
  32. 32.Best estimate of 1743 ÷ 32? (a) 580 (b) 5800 (c) 58
  33. 33.Best estimate of 3015 ÷ 34? (a) 1010 (b) 101 (c) 10100
  34. 34.Best estimate of 740 ÷ 52? (a) 15 (b) 150 (c) 1500
  35. 35.√42 to 1 decimal place? (a) 6.3 (b) 6.5 (c) 6.6 (d) 6.4
  36. 36.Best estimate of 2462 ÷ 26? (a) 82 (b) 8200 (c) 820
  37. 37.Best estimate of 1866 ÷ 22? (a) 930 (b) 93 (c) 9300
  38. 38.√30 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.4 (d) 5.7
  39. 39.Best estimate of 2944 ÷ 72? (a) 42 (b) 4200 (c) 420
  40. 40.√34 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 6.1

Answer key

  1. 40
  2. 71
  3. 9.1
  4. 91
  5. 66
  6. 81
  7. 6.9
  8. 33
  9. 26
  10. 8.4
  11. 7.3
  12. 56
  13. 37
  14. 6.2
  15. 31
  16. 63
  17. 33
  18. 49
  19. 8.3
  20. 28
  21. 41
  22. 9.2
  23. 6.1
  24. 89
  25. 59
  26. 100
  27. 4.7
  28. 7.9
  29. 86
  30. 5.9
  31. 9.8
  32. 58
  33. 101
  34. 15
  35. 6.5
  36. 82
  37. 93
  38. 5.5
  39. 42
  40. 5.8

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