← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 692 · 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 3872 ÷ 42? (a) 970 (b) 97 (c) 9700
  2. 2.Best estimate of 4929 ÷ 66? (a) 7000 (b) 70 (c) 700
  3. 3.Best estimate of 1934 ÷ 69? (a) 2800 (b) 28 (c) 280
  4. 4.Best estimate of 1593 ÷ 29? (a) 53 (b) 530 (c) 5300
  5. 5.Best estimate of 4475 ÷ 82? (a) 5600 (b) 560 (c) 56
  6. 6.√41 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.2 (d) 6.3
  7. 7.Best estimate of 923 ÷ 57? (a) 15 (b) 1500 (c) 150
  8. 8.Best estimate of 1315 ÷ 74? (a) 19 (b) 190 (c) 1900
  9. 9.Best estimate of 4363 ÷ 66? (a) 62 (b) 620 (c) 6200
  10. 10.Best estimate of 6655 ÷ 72? (a) 950 (b) 9500 (c) 95
  11. 11.Best estimate of 5538 ÷ 78? (a) 69 (b) 6900 (c) 690
  12. 12.√22 to 1 decimal place? (a) 4.8 (b) 4.7 (c) 5.0 (d) 4.9
  13. 13.Best estimate of 4732 ÷ 66? (a) 680 (b) 6800 (c) 68
  14. 14.Best estimate of 2391 ÷ 62? (a) 4000 (b) 40 (c) 400
  15. 15.√67 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.2 (d) 8.4
  16. 16.√23 to 1 decimal place? (a) 4.8 (b) 4.7 (c) 4.9 (d) 5.0
  17. 17.Best estimate of 7933 ÷ 86? (a) 88 (b) 8800 (c) 880
  18. 18.Best estimate of 2069 ÷ 42? (a) 52 (b) 520 (c) 5200
  19. 19.√43 to 1 decimal place? (a) 6.9 (b) 6.8 (c) 6.6 (d) 6.7
  20. 20.Best estimate of 1468 ÷ 86? (a) 16 (b) 160 (c) 1600
  21. 21.√24 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 5.0 (d) 4.9
  22. 22.√70 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.2 (d) 8.1
  23. 23.√55 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.4 (d) 7.1
  24. 24.√61 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 7.8 (d) 7.9
  25. 25.Best estimate of 6092 ÷ 86? (a) 6800 (b) 68 (c) 680
  26. 26.Best estimate of 1366 ÷ 58? (a) 23 (b) 230 (c) 2300
  27. 27.Best estimate of 2418 ÷ 26? (a) 8100 (b) 81 (c) 810
  28. 28.Best estimate of 4028 ÷ 81? (a) 5000 (b) 500 (c) 50
  29. 29.√98 to 1 decimal place? (a) 9.7 (b) 10.0 (c) 9.9 (d) 9.8
  30. 30.√78 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.9 (d) 8.8
  31. 31.√90 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.5 (d) 9.4
  32. 32.Best estimate of 1423 ÷ 43? (a) 360 (b) 3600 (c) 36
  33. 33.√40 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.3
  34. 34.√74 to 1 decimal place? (a) 8.5 (b) 8.8 (c) 8.7 (d) 8.6
  35. 35.Best estimate of 2461 ÷ 51? (a) 490 (b) 49 (c) 4900
  36. 36.√63 to 1 decimal place? (a) 7.8 (b) 8.1 (c) 8.0 (d) 7.9
  37. 37.√31 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.8 (d) 5.9
  38. 38.√84 to 1 decimal place? (a) 9.2 (b) 9.5 (c) 9.3 (d) 9.4
  39. 39.Best estimate of 1781 ÷ 26? (a) 590 (b) 5900 (c) 59
  40. 40.√96 to 1 decimal place? (a) 10.1 (b) 10.0 (c) 9.9 (d) 9.8

Answer key

  1. 97
  2. 70
  3. 28
  4. 53
  5. 56
  6. 6.4
  7. 15
  8. 19
  9. 62
  10. 95
  11. 69
  12. 4.7
  13. 68
  14. 40
  15. 8.2
  16. 4.8
  17. 88
  18. 52
  19. 6.6
  20. 16
  21. 4.9
  22. 8.4
  23. 7.4
  24. 7.8
  25. 68
  26. 23
  27. 81
  28. 50
  29. 9.9
  30. 8.8
  31. 9.5
  32. 36
  33. 6.3
  34. 8.6
  35. 49
  36. 7.9
  37. 5.6
  38. 9.2
  39. 59
  40. 9.8

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