CCNA Subnetting Made Easy Part 01 - English

Subnetting is an important topic when it comes to networking, through practising some question I will guide you on how to easily find solutions for all related subnetting questions.
let's get started :
1- the first possible question regarding subnetting is finding subnet mask from shorthand or CIDR 

if you have a question like this you can easily find the subnet mask from the CIDR, the first step is to convert the CIDR to binary, then convert it to a number as below :

we have 24 which mean 24 bits are 1 and the rest should be 0

each bit in the binary represent a number as below

so now if you have a question asking to find subnetmask from CIDR 27, You can do is as follow:
1- convert 27 to binary: 11111111.11111111.11111111.11100000
2- convert binary to no.  255          255           255          (128+64+32=224)
so now the  subnet mask is 255.255.255.224 for CIDR 27

for more information watch this video.

to watch part two click this link : Part two

to watch part three click this link : Part three