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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 299 · 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.√45 to 1 decimal place? (a) 6.5 (b) 6.7 (c) 6.6 (d) 6.8
  2. 2.√83 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.2 (d) 8.9
  3. 3.√37 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 6.1 (d) 5.9
  4. 4.Best estimate of 2050 ÷ 71? (a) 29 (b) 2900 (c) 290
  5. 5.√61 to 1 decimal place? (a) 7.8 (b) 7.6 (c) 7.7 (d) 7.5
  6. 6.√78 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 8.8 (d) 9.0
  7. 7.Best estimate of 3996 ÷ 57? (a) 67 (b) 670 (c) 6700
  8. 8.√55 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.3 (d) 7.2
  9. 9.Best estimate of 6455 ÷ 68? (a) 92 (b) 920 (c) 9200
  10. 10.√65 to 1 decimal place? (a) 8.0 (b) 8.3 (c) 8.1 (d) 8.2
  11. 11.Best estimate of 462 ÷ 22? (a) 2300 (b) 230 (c) 23
  12. 12.√41 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  13. 13.√52 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.0 (d) 7.3
  14. 14.Best estimate of 4734 ÷ 83? (a) 590 (b) 59 (c) 5900
  15. 15.Best estimate of 1630 ÷ 29? (a) 5400 (b) 540 (c) 54
  16. 16.Best estimate of 2169 ÷ 36? (a) 54 (b) 540 (c) 5400
  17. 17.Best estimate of 3985 ÷ 42? (a) 1000 (b) 10000 (c) 100
  18. 18.√71 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.1 (d) 8.2
  19. 19.Best estimate of 2785 ÷ 32? (a) 930 (b) 93 (c) 9300
  20. 20.Best estimate of 695 ÷ 24? (a) 35 (b) 3500 (c) 350
  21. 21.Best estimate of 1982 ÷ 52? (a) 4000 (b) 400 (c) 40
  22. 22.√88 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.7 (d) 9.5
  23. 23.Best estimate of 2881 ÷ 78? (a) 3600 (b) 36 (c) 360
  24. 24.Best estimate of 1685 ÷ 82? (a) 21 (b) 2100 (c) 210
  25. 25.Best estimate of 4417 ÷ 48? (a) 8800 (b) 880 (c) 88
  26. 26.√31 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 5.6 (d) 5.7
  27. 27.Best estimate of 1218 ÷ 26? (a) 4100 (b) 41 (c) 410
  28. 28.Best estimate of 4117 ÷ 59? (a) 6900 (b) 69 (c) 690
  29. 29.√56 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.8 (d) 7.5
  30. 30.Best estimate of 630 ÷ 28? (a) 21 (b) 210 (c) 2100
  31. 31.√85 to 1 decimal place? (a) 9.2 (b) 9.0 (c) 9.1 (d) 9.3
  32. 32.Best estimate of 1611 ÷ 63? (a) 2700 (b) 270 (c) 27
  33. 33.Best estimate of 1399 ÷ 33? (a) 470 (b) 4700 (c) 47
  34. 34.√82 to 1 decimal place? (a) 8.9 (b) 9.2 (c) 9.1 (d) 9.0
  35. 35.√67 to 1 decimal place? (a) 8.3 (b) 8.0 (c) 8.2 (d) 8.1
  36. 36.Best estimate of 2539 ÷ 48? (a) 510 (b) 51 (c) 5100
  37. 37.Best estimate of 592 ÷ 36? (a) 150 (b) 15 (c) 1500
  38. 38.√32 to 1 decimal place? (a) 5.6 (b) 5.7 (c) 5.8 (d) 5.5
  39. 39.Best estimate of 975 ÷ 39? (a) 24 (b) 2400 (c) 240
  40. 40.√62 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 7.9 (d) 8.1

Answer key

  1. 6.7
  2. 9.1
  3. 6.1
  4. 29
  5. 7.8
  6. 8.8
  7. 67
  8. 7.4
  9. 92
  10. 8.1
  11. 23
  12. 6.4
  13. 7.2
  14. 59
  15. 54
  16. 54
  17. 100
  18. 8.4
  19. 93
  20. 35
  21. 40
  22. 9.4
  23. 36
  24. 21
  25. 88
  26. 5.6
  27. 41
  28. 69
  29. 7.5
  30. 21
  31. 9.2
  32. 27
  33. 47
  34. 9.1
  35. 8.2
  36. 51
  37. 15
  38. 5.7
  39. 24
  40. 7.9

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