A CIDR address of /24 provides 254 assignable IP addresses, accounting for one network address and one broadcast address which cannot be assigned to hosts.
Given a CIDR address of /24, the number of assignable IP addresses is 254. A /24 indicates a subnet mask of 255.255.255.0, which allows for 256 total IP addresses. However, one address is reserved for the network address and one for the broadcast address, thus leaving 254 addresses available for assignment to hosts within the network.