Find th size of the global unicast block from the table

Prefixes for assigned IPv$6$ addresses

Block prefix CIDR Block assignment Fraction

$000000000000$::$/8$ Special addresses $1/256$

$0012000$::$/3$ Global unicast $1/8$

$1111110$ FC$00$::$/7$ Unique local unicast $1/128$

$1111111010$ FE$80$::$/10$ Link local addresses $1/1024$

$11111111$ FF$00$::$/8$ Multicast addresses $1/256$