6,8/7,7-5,9/15,4

To calculate the expression \( \frac{6.8}{7.7} - \frac{5.9}{15.4} \), we can follow these steps:

1. Calculate \( \frac{6.8}{7.7} \):

   \[ \frac{6.8}{7.7} \approx 0.8825 \]

2. Calculate \( \frac{5.9}{15.4} \):

   \[ \frac{5.9}{15.4} \approx 0.3839 \]

3. Now, subtract the two results:

   \[ 0.8825 - 0.3839 \approx 0.4986 \]

Thus, the result of the expression \( \frac{6.8}{7.7} - \frac{5.9}{15.4} \) is approximately \( 0.4986 \).