CCENT/CCNA ICND1 100-101 Official Cert Guide

Mask Conversion Problem 9: Answer

The answer is 255.255.252.0.

For problem 9, with a prefix of /22, you start at Step 1 by writing down 22 binary 1s, as shown here:

11111111 11111111 111111

At Step 2, you add binary 0s until you have 32 total bits, as shown next:

11111111 11111111 11111100 00000000

The only remaining work is to convert this 32-bit number to decimal, remembering that the conversion works with 8 bits at a time.