Converting Between Decimal Numbers and Binary

In any given octet of an IP address, the 8 bits can be defined as follows:

27	26	25	24	23	22	21	20
128	64	32	16	8	4	2	1

To convert a decimal number into binary, you must turn on the bits (make them a 1) that would add up to that number, as follows:

          187 = 10111011 = 128+32+16+8+2+1
          224 = 11100000 = 128+64+32

To convert a binary number into decimal, you must add the bits that have been turned on (the 1s), as follows:

          10101010 = 128+32+8+2 = 170
          11110000 = 128+64+32+16 = 240

The IP address 138.101.114.250 is represented in binary as:

          10001010.01100101.01110010.11111010

The subnet mask of 255.255.255.192 is represented in binary as:

          11111111.11111111.11111111.11000000