Figure 1 shows the first three bits in an IPv6 global unicast address are set to 001.  The figure shows the range of binary bits for the first hextet to be from 2000 to 3FFF. Figure 2 shows the IPv6 global routing prefix of /48.  The first 48 bits serve as the global routing prefix and the next sixteen bits are used as a subnet identifier.  The /48 routing prefix plus the 16 bit subnet identifier form the /64 prefix.   The remaining 64 bits are the interface identifier. Figure 3 shows how to read a global unicast address.  The address is listed first as a compressed address, 2001:DB8:ACAD:1::10/64.  The first four hextets is the prefix and the last four hextets is the interface identifier.  This expands to 2001:0DB8:ACAD:0001:0000:0000:0000:0010 /64.  The global routing prefix is 2001:0DB8:ACAD.  The subnet ID is 0001 and the interface ID is 0000:0000:0000:0200.