Hello Ali.
A class A address will have 8 bits for the network portion of the address and 24 bits for the host portion. Therefore the host portion can define up to 2^24 host addresses (minus two for the network and broadcast addresses). That’s 16,777,214 host addresses per network.
A class B address will have 16 bits for the network portion of the address and 16 bits for the host portion. Therefore the host portion can define up to 2^16 host addresses (minus two for the network and broadcast addresses). That’s 65,534 host addresses per network.
A class C address will have 24 bits for the network portion of the address and 8 bits for the host portion. Therefore the host portion can define up to 2^8 host addresses (minus two for the network and broadcast addresses). That’s 254 host addresses per network.
I hope this has been helpful!
Laz