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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 694 · 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 715 ÷ 28? (a) 240 (b) 2400 (c) 24
  2. 2.√86 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.5 (d) 9.3
  3. 3.√69 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.3 (d) 8.6
  4. 4.Best estimate of 2365 ÷ 36? (a) 590 (b) 5900 (c) 59
  5. 5.Best estimate of 2956 ÷ 36? (a) 740 (b) 74 (c) 7400
  6. 6.Best estimate of 2007 ÷ 82? (a) 250 (b) 25 (c) 2500
  7. 7.√65 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 8.1 (d) 7.8
  8. 8.Best estimate of 2205 ÷ 49? (a) 4400 (b) 440 (c) 44
  9. 9.√58 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.6 (d) 7.5
  10. 10.√37 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 5.9 (d) 6.1
  11. 11.√84 to 1 decimal place? (a) 9.2 (b) 8.9 (c) 9.1 (d) 9.0
  12. 12.Best estimate of 868 ÷ 32? (a) 290 (b) 29 (c) 2900
  13. 13.√26 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.0 (d) 5.2
  14. 14.Best estimate of 2759 ÷ 32? (a) 9200 (b) 920 (c) 92
  15. 15.√94 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.7 (d) 9.5
  16. 16.√92 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 9.6 (d) 9.7
  17. 17.Best estimate of 4464 ÷ 59? (a) 74 (b) 740 (c) 7400
  18. 18.Best estimate of 1982 ÷ 22? (a) 9900 (b) 990 (c) 99
  19. 19.√96 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 9.8 (d) 10.0
  20. 20.√76 to 1 decimal place? (a) 8.5 (b) 8.8 (c) 8.7 (d) 8.6
  21. 21.Best estimate of 2392 ÷ 68? (a) 3400 (b) 34 (c) 340
  22. 22.√55 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.4 (d) 7.3
  23. 23.Best estimate of 3016 ÷ 62? (a) 50 (b) 5000 (c) 500
  24. 24.Best estimate of 1432 ÷ 23? (a) 720 (b) 72 (c) 7200
  25. 25.Best estimate of 1241 ÷ 63? (a) 2100 (b) 210 (c) 21
  26. 26.√27 to 1 decimal place? (a) 5.0 (b) 4.9 (c) 5.1 (d) 5.2
  27. 27.Best estimate of 3322 ÷ 47? (a) 66 (b) 660 (c) 6600
  28. 28.√61 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.0 (d) 7.8
  29. 29.Best estimate of 1160 ÷ 39? (a) 2900 (b) 290 (c) 29
  30. 30.Best estimate of 4376 ÷ 52? (a) 88 (b) 8800 (c) 880
  31. 31.Best estimate of 2944 ÷ 36? (a) 74 (b) 740 (c) 7400
  32. 32.√90 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.3 (d) 9.2
  33. 33.Best estimate of 3988 ÷ 56? (a) 6600 (b) 66 (c) 660
  34. 34.Best estimate of 7062 ÷ 83? (a) 8800 (b) 880 (c) 88
  35. 35.Best estimate of 2818 ÷ 46? (a) 56 (b) 560 (c) 5600
  36. 36.√62 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.6 (d) 7.9
  37. 37.Best estimate of 2125 ÷ 38? (a) 530 (b) 5300 (c) 53
  38. 38.Best estimate of 567 ÷ 26? (a) 19 (b) 1900 (c) 190
  39. 39.√74 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.6 (d) 8.4
  40. 40.Best estimate of 5874 ÷ 87? (a) 650 (b) 65 (c) 6500

Answer key

  1. 24
  2. 9.3
  3. 8.3
  4. 59
  5. 74
  6. 25
  7. 8.1
  8. 44
  9. 7.6
  10. 6.1
  11. 9.2
  12. 29
  13. 5.1
  14. 92
  15. 9.7
  16. 9.6
  17. 74
  18. 99
  19. 9.8
  20. 8.7
  21. 34
  22. 7.4
  23. 50
  24. 72
  25. 21
  26. 5.2
  27. 66
  28. 7.8
  29. 29
  30. 88
  31. 74
  32. 9.5
  33. 66
  34. 88
  35. 56
  36. 7.9
  37. 53
  38. 19
  39. 8.6
  40. 65

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