← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 172 · 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 3381 ÷ 37? (a) 850 (b) 8500 (c) 85
  2. 2.√62 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 8.0 (d) 7.9
  3. 3.√34 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 6.1 (d) 5.8
  4. 4.√94 to 1 decimal place? (a) 9.7 (b) 10.0 (c) 9.8 (d) 9.9
  5. 5.√40 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.5 (d) 6.3
  6. 6.Best estimate of 3422 ÷ 56? (a) 57 (b) 570 (c) 5700
  7. 7.√43 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.9 (d) 6.7
  8. 8.Best estimate of 2926 ÷ 44? (a) 7300 (b) 73 (c) 730
  9. 9.√59 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 8.0 (d) 7.8
  10. 10.√87 to 1 decimal place? (a) 9.0 (b) 9.3 (c) 9.2 (d) 9.1
  11. 11.√20 to 1 decimal place? (a) 4.4 (b) 4.5 (c) 4.3 (d) 4.2
  12. 12.Best estimate of 1616 ÷ 24? (a) 810 (b) 8100 (c) 81
  13. 13.√30 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.3 (d) 5.2
  14. 14.Best estimate of 1465 ÷ 42? (a) 3700 (b) 370 (c) 37
  15. 15.√50 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.1 (d) 7.2
  16. 16.Best estimate of 2496 ÷ 66? (a) 3600 (b) 360 (c) 36
  17. 17.Best estimate of 1959 ÷ 24? (a) 9800 (b) 980 (c) 98
  18. 18.√69 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.1 (d) 8.2
  19. 19.√76 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.7 (d) 8.5
  20. 20.Best estimate of 879 ÷ 68? (a) 130 (b) 13 (c) 1300
  21. 21.√98 to 1 decimal place? (a) 9.6 (b) 9.9 (c) 9.8 (d) 9.7
  22. 22.√96 to 1 decimal place? (a) 10.0 (b) 10.1 (c) 9.8 (d) 9.9
  23. 23.√37 to 1 decimal place? (a) 6.0 (b) 6.2 (c) 5.9 (d) 6.1
  24. 24.√53 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.2 (d) 7.3
  25. 25.Best estimate of 6650 ÷ 84? (a) 830 (b) 83 (c) 8300
  26. 26.Best estimate of 1615 ÷ 66? (a) 23 (b) 2300 (c) 230
  27. 27.Best estimate of 1390 ÷ 27? (a) 4600 (b) 460 (c) 46
  28. 28.Best estimate of 2565 ÷ 52? (a) 51 (b) 5100 (c) 510
  29. 29.√67 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.3 (d) 8.0
  30. 30.Best estimate of 4744 ÷ 52? (a) 95 (b) 950 (c) 9500
  31. 31.√78 to 1 decimal place? (a) 8.8 (b) 8.6 (c) 8.5 (d) 8.7
  32. 32.Best estimate of 1953 ÷ 76? (a) 2400 (b) 240 (c) 24
  33. 33.√35 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 5.9
  34. 34.Best estimate of 5468 ÷ 83? (a) 68 (b) 680 (c) 6800
  35. 35.√79 to 1 decimal place? (a) 8.8 (b) 9.0 (c) 8.7 (d) 8.9
  36. 36.√48 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 7.0
  37. 37.√75 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 8.7 (d) 9.0
  38. 38.Best estimate of 1626 ÷ 88? (a) 18 (b) 180 (c) 1800
  39. 39.Best estimate of 1640 ÷ 82? (a) 21 (b) 210 (c) 2100
  40. 40.√26 to 1 decimal place? (a) 5.3 (b) 5.2 (c) 5.4 (d) 5.1

Answer key

  1. 85
  2. 7.9
  3. 5.8
  4. 9.7
  5. 6.3
  6. 57
  7. 6.6
  8. 73
  9. 7.7
  10. 9.3
  11. 4.5
  12. 81
  13. 5.5
  14. 37
  15. 7.1
  16. 36
  17. 98
  18. 8.3
  19. 8.7
  20. 13
  21. 9.9
  22. 9.8
  23. 6.1
  24. 7.3
  25. 83
  26. 23
  27. 46
  28. 51
  29. 8.2
  30. 95
  31. 8.8
  32. 24
  33. 5.9
  34. 68
  35. 8.9
  36. 6.9
  37. 8.7
  38. 18
  39. 21
  40. 5.1

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