This simulation does EIGRP summary-address for both IPv4 and IPv6 addresses. The left side has the summary address commands for it. The right side is a mirror of the configuration and is left alone.
iosv2 in interface g0/1 has the summary address commands.
The loop back addresses are /128. I used a /126 for the 3 loopback addresses and /125 for 7 loopbacks.
The math works out as you start with /128. 3 addresses would be 00 to 11 so two places. so you move 128 left to 126. The 7 addresses would be 000 to 111, so 3 places. 128 left to 125. The interesting one was fd00:192:168:48:0/64 and fd00:192:168:49:0/64. The summary of 2 addresses moved from 64 left to 63.
From iosv1, I can ping all the addresses that are summarized.
The bottom routers have 3 loopbacks and 7 loopbacks