← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 73 · 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.√74 to 1 decimal place? (a) 8.7 (b) 8.4 (c) 8.5 (d) 8.6
  2. 2.√42 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.4 (d) 6.5
  3. 3.√32 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 5.7 (d) 5.8
  4. 4.√65 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 7.9 (d) 7.8
  5. 5.√37 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 6.2 (d) 6.1
  6. 6.√76 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.4
  7. 7.Best estimate of 3045 ÷ 62? (a) 51 (b) 510 (c) 5100
  8. 8.√21 to 1 decimal place? (a) 4.6 (b) 4.4 (c) 4.7 (d) 4.5
  9. 9.√71 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.3 (d) 8.5
  10. 10.√59 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.7 (d) 7.5
  11. 11.Best estimate of 2786 ÷ 89? (a) 310 (b) 31 (c) 3100
  12. 12.Best estimate of 1019 ÷ 41? (a) 25 (b) 250 (c) 2500
  13. 13.Best estimate of 1121 ÷ 76? (a) 1400 (b) 14 (c) 140
  14. 14.Best estimate of 3481 ÷ 82? (a) 440 (b) 44 (c) 4400
  15. 15.√58 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.8 (d) 7.7
  16. 16.√24 to 1 decimal place? (a) 4.7 (b) 4.9 (c) 5.0 (d) 4.8
  17. 17.√70 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.4 (d) 8.1
  18. 18.Best estimate of 3576 ÷ 82? (a) 450 (b) 4500 (c) 45
  19. 19.Best estimate of 2433 ÷ 27? (a) 8100 (b) 81 (c) 810
  20. 20.√34 to 1 decimal place? (a) 6.1 (b) 5.8 (c) 6.0 (d) 5.9
  21. 21.√75 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.4 (d) 8.6
  22. 22.Best estimate of 2908 ÷ 66? (a) 420 (b) 42 (c) 4200
  23. 23.Best estimate of 1787 ÷ 24? (a) 89 (b) 890 (c) 8900
  24. 24.Best estimate of 1124 ÷ 23? (a) 560 (b) 5600 (c) 56
  25. 25.√90 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.5 (d) 9.6
  26. 26.Best estimate of 3555 ÷ 79? (a) 440 (b) 4400 (c) 44
  27. 27.√55 to 1 decimal place? (a) 7.3 (b) 7.5 (c) 7.6 (d) 7.4
  28. 28.√53 to 1 decimal place? (a) 7.1 (b) 7.3 (c) 7.4 (d) 7.2
  29. 29.Best estimate of 1658 ÷ 22? (a) 830 (b) 8300 (c) 83
  30. 30.√69 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.2 (d) 8.5
  31. 31.Best estimate of 545 ÷ 41? (a) 140 (b) 14 (c) 1400
  32. 32.Best estimate of 3792 ÷ 42? (a) 95 (b) 9500 (c) 950
  33. 33.√94 to 1 decimal place? (a) 9.5 (b) 9.7 (c) 9.6 (d) 9.4
  34. 34.√61 to 1 decimal place? (a) 7.6 (b) 7.8 (c) 7.7 (d) 7.5
  35. 35.Best estimate of 2539 ÷ 38? (a) 63 (b) 6300 (c) 630
  36. 36.Best estimate of 1065 ÷ 44? (a) 2700 (b) 27 (c) 270
  37. 37.Best estimate of 2536 ÷ 47? (a) 5100 (b) 51 (c) 510
  38. 38.√96 to 1 decimal place? (a) 10.1 (b) 10.0 (c) 9.9 (d) 9.8
  39. 39.Best estimate of 737 ÷ 33? (a) 25 (b) 250 (c) 2500
  40. 40.Best estimate of 921 ÷ 22? (a) 4600 (b) 460 (c) 46

Answer key

  1. 8.6
  2. 6.5
  3. 5.7
  4. 8.1
  5. 6.1
  6. 8.7
  7. 51
  8. 4.6
  9. 8.4
  10. 7.7
  11. 31
  12. 25
  13. 14
  14. 44
  15. 7.6
  16. 4.9
  17. 8.4
  18. 45
  19. 81
  20. 5.8
  21. 8.7
  22. 42
  23. 89
  24. 56
  25. 9.5
  26. 44
  27. 7.4
  28. 7.3
  29. 83
  30. 8.3
  31. 14
  32. 95
  33. 9.7
  34. 7.8
  35. 63
  36. 27
  37. 51
  38. 9.8
  39. 25
  40. 46

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths