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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 265 · 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 1798 ÷ 24? (a) 90 (b) 900 (c) 9000
  2. 2.Best estimate of 3492 ÷ 72? (a) 50 (b) 5000 (c) 500
  3. 3.Best estimate of 2896 ÷ 69? (a) 410 (b) 41 (c) 4100
  4. 4.Best estimate of 1726 ÷ 28? (a) 5800 (b) 580 (c) 58
  5. 5.Best estimate of 3571 ÷ 42? (a) 890 (b) 89 (c) 8900
  6. 6.Best estimate of 3575 ÷ 71? (a) 5100 (b) 51 (c) 510
  7. 7.√53 to 1 decimal place? (a) 7.3 (b) 7.0 (c) 7.2 (d) 7.1
  8. 8.Best estimate of 1896 ÷ 22? (a) 9500 (b) 95 (c) 950
  9. 9.√34 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 5.6 (d) 5.8
  10. 10.Best estimate of 1884 ÷ 76? (a) 24 (b) 2400 (c) 240
  11. 11.√78 to 1 decimal place? (a) 8.8 (b) 8.9 (c) 8.7 (d) 9.0
  12. 12.Best estimate of 3571 ÷ 52? (a) 710 (b) 71 (c) 7100
  13. 13.√80 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 8.8 (d) 9.0
  14. 14.Best estimate of 572 ÷ 26? (a) 1900 (b) 19 (c) 190
  15. 15.Best estimate of 740 ÷ 37? (a) 1900 (b) 19 (c) 190
  16. 16.Best estimate of 3413 ÷ 72? (a) 4900 (b) 490 (c) 49
  17. 17.√92 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.4 (d) 9.3
  18. 18.Best estimate of 1431 ÷ 23? (a) 72 (b) 720 (c) 7200
  19. 19.Best estimate of 2357 ÷ 41? (a) 5900 (b) 590 (c) 59
  20. 20.Best estimate of 3952 ÷ 64? (a) 6600 (b) 66 (c) 660
  21. 21.Best estimate of 1254 ÷ 67? (a) 1800 (b) 18 (c) 180
  22. 22.√65 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.0 (d) 8.3
  23. 23.√40 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 6.2 (d) 6.3
  24. 24.Best estimate of 923 ÷ 37? (a) 2300 (b) 230 (c) 23
  25. 25.Best estimate of 1874 ÷ 72? (a) 2700 (b) 27 (c) 270
  26. 26.Best estimate of 736 ÷ 26? (a) 25 (b) 250 (c) 2500
  27. 27.Best estimate of 2866 ÷ 67? (a) 41 (b) 4100 (c) 410
  28. 28.Best estimate of 1680 ÷ 32? (a) 560 (b) 5600 (c) 56
  29. 29.√37 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.4 (d) 6.1
  30. 30.√67 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 7.9 (d) 8.1
  31. 31.√70 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.4
  32. 32.Best estimate of 5353 ÷ 86? (a) 5900 (b) 590 (c) 59
  33. 33.Best estimate of 952 ÷ 62? (a) 1600 (b) 160 (c) 16
  34. 34.√48 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 7.2 (d) 7.1
  35. 35.√26 to 1 decimal place? (a) 5.1 (b) 5.4 (c) 5.2 (d) 5.3
  36. 36.√55 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.4 (d) 7.7
  37. 37.Best estimate of 1377 ÷ 28? (a) 46 (b) 460 (c) 4600
  38. 38.Best estimate of 3204 ÷ 67? (a) 46 (b) 4600 (c) 460
  39. 39.√44 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.4 (d) 6.5
  40. 40.√98 to 1 decimal place? (a) 10.0 (b) 10.2 (c) 10.1 (d) 9.9

Answer key

  1. 90
  2. 50
  3. 41
  4. 58
  5. 89
  6. 51
  7. 7.3
  8. 95
  9. 5.8
  10. 24
  11. 8.8
  12. 71
  13. 8.9
  14. 19
  15. 19
  16. 49
  17. 9.6
  18. 72
  19. 59
  20. 66
  21. 18
  22. 8.1
  23. 6.3
  24. 23
  25. 27
  26. 25
  27. 41
  28. 56
  29. 6.1
  30. 8.2
  31. 8.4
  32. 59
  33. 16
  34. 6.9
  35. 5.1
  36. 7.4
  37. 46
  38. 46
  39. 6.6
  40. 9.9

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