Conversion Between Decimal Numbers and Binary
In the 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

For 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:
188 = 10111100 = 128+32+16+8+4
224 = 11100000 = 128+64+32
To convert a
binary number into decimal, we 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 192.168.100.1 is represented in binary as
11000000.10101000.01100100 .00000001
The subnet mask of 255.255.255.128 is represented in binary as
11111111.11111111.11111111.1 0000000
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