Subnet a network( 203.230.7.0/24 )

Biggest Network

11 IP addresses are required including switches, network ID, and broadcast address.
Therefore, the bitmask would be 28

VLSM(Variable Length Subnet MasK)

If networks between two routers are assigned 28-bit network, 12 addresses are wasted. Accordingly, a network is divided once again into 30-bit networks, in that each network between two routers needs four addresses.

The smaller networks

follw the biggests' subnet basically