Hi!
Good day! It depends on your requirement. Usually, Class A networks could provide you a maximum of 126 networks and a maximum of 16,777,215 hosts using the default subnet mask of 255.0.0.0 or /8. Who would require such a number of host, right? Due to certain limitations of IPv4 especially when it comes to the number of host addresses, Variable Length Subnet Masking (VLSM) was developed for a more efficient use of ip addressing. Also, addresses on different classes was assigned for private use, like in the case of class A addresses, 10.0.0.0 to 10.255.255.255 was given. Now if you are a private company that would require an ip addressing scheme for lets say 240 hosts, given the private class A pool, you can use 10.0.0.0 for your network but using the default subnet of /8 would give you 16 million hosts, so instead using VLSM you can use a /24 subnet giving you 254 hosts enough for your 240 host requirement.
Hope this helps,
Regards,
Albert