There are 16 bits available; it is up to you how many of those bits you reserve for the subnet, and how many for the individual hosts within each subnet.
1
You would need at least 9 bits to borrow. Since 8 bits gives only 255 the additional bit will get you 256. Adding 256 + 128 gives you at least 384 subnets or hosts.
255.255.252.0
255.255.252.0
A class A would give you the most flexibility in terms of subnets and hosts per subnet. You could use up to 23 bits of information for subnets.
that gives you 16 subnets with 14 usable IPs for hosts that is because one is for subnet and one for broadcas in that subnet for example: 192.168.1.0/28 - subnet number 192.168.1.15 -broadcast number usable IPs for hosts - IPs between them that is 14
255.255.252.0
254
To calculate a subnet mask, first determine the number of subnets needed and the number of hosts per subnet. Use the formula (2^n \geq \text{number of subnets}) for subnetting and (2^h - 2 \geq \text{number of hosts}) for host calculation, where (n) is the number of bits borrowed for subnets and (h) is the number of bits left for hosts. For example, if you start with a Class C address like 192.168.1.0 and want 4 subnets, you would borrow 2 bits (since (2^2 = 4)), resulting in a subnet mask of 255.255.255.192 (or /26), which allows for 62 hosts per subnet.
Given a Class C network: 200.1.1.0 We want 5 subnets, each with 30 hosts on it. How many bits to borrow ? How many bits to leave? What is the subnet mask? ( in dot notation and in CIDR notation)
There are 65,536 subnets available in an IPv6 /48 block.