The Idea of a Default Static Route is: If the Router does not know the address pass the packet to a Router with a broader scope
192.168.10.0/24 2001:db8:acad:10::/64
192.168.20.0/24 2001:db8:acad:20::/64
172.16.10.0/24 2001:db8:cafe:10::/64
172.16.20.0/24 2001:db8:cafe:10::/64
172.16.0.0/30 2001:db8:cafe:0::/64
192.168.0.0/30 2001:db8:acad:0::/64
192.168.0.2
2001:db8:acad:0::2
The commands are shown below for router 3, but Router 2 and Router 1 may also have Default Static routes