Hello is there anyone who could explain how to get the answer for this lab?

I googled the answer
CCNA1 Lab 6.7.5 Answers

And would like to understand this particular lab, it wrote
You have been given the 192.1681.0/24 but what is it /27 in step 2, when asked What is the subnet mask for the network in slash format.



Thanks to those who could explain it!
Appreciate much,
Regards Yubin