For some reason, this question has me lost - particular cidr question
Which of the following IP addresses fall into the CIDR block of
110.68.4.0/18?
a) 110.68.8.32 b) 110.68.7.64 c) 110.67.6.255 d) 110.66.3.254 e) 110.65.5.128 f) 110.64.12.128
Book lists answers as B,C,E.
I see /18 meaning block size of size of 64. I do know this is a class A address being "110".
Some reason I am stumped on this one. Any help appreciated.