We have 3×3/5, 2×4/7, 1×9/6, 1×8/8

3×3/5 = (3 × 5 + 3)/5 = 18/5

2×4/7 = (2 × 7 + 4)/7 = 18/7

Improper fractions: 18/5, 18/7, 19/6, 18/8

LCM of denominators (5, 7, 6, 8):

LCM = 2 × 2 × 2 × 3 × 5 × 7 = 840

Making denominators same:

18/5 = (18 × 168)/(5 × 168) = 3024/840

18/7 = (18 × 120)/(7 × 120) = 2160/840

19/6 = (19 × 140)/(6 × 140) = 2660/840

18/8 = (18 × 105)/(8 × 105) = 1890/840

Here 3024/840 or 18/5 is the greatest fraction and 1890/840 or 18/8 is the smallest fraction.

Difference = 18/5 - 18/8

= (18 × 8)/(5 × 8) - (18 × 5)/(8 × 5)

= 144/40 - 90/40

= 54/40 = 27/20

Hence the required difference = 27/20 or 1×(7/20)