so let's say you're taking the CCENT exam and it asks a question like: Which ip addresses falls withing the range of the given ip?
a) 220.127.116.11 /21
b) 18.104.22.168 /21
c) 22.214.171.124 /21
d) 126.96.36.199 /21
On the CCENT/CCNA ICND1 Official Exam Cert cd it tells you to use the 'magic' number to get multiples of 8. The cd states that you should be able to do this in 15 seconds. How is this possible, is there another formula I can use? Please do the math before responding. Thank you.