Partition #3 contains a ntfs signature.
passwd: password expiry information changed.
dbus-daemon[812]: [session uid=999 pid=812] Activating service name='org.gtk.vfs.Daemon' requested by ':1.0' (uid=999 pid=813 comm="" label="unconfined")
dbus-daemon[812]: [session uid=999 pid=812] Successfully activated service 'org.gtk.vfs.Daemon'
dbus-daemon[812]: [session uid=999 pid=812] Activating service name='org.gtk.vfs.Metadata' requested by ':1.0' (uid=999 pid=813 comm="" label="unconfined")
fuse: device not found, try 'modprobe fuse' first
dbus-daemon[812]: [session uid=999 pid=812] Successfully activated service 'org.gtk.vfs.Metadata'
A connection to the bus can't be made
Using CD-ROM mount point /cdrom/
Identifying... [36a2f3e719449f3a7bac9fddca1c4551-2]
Scanning disc for index files...
Found 4 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
Found label 'Ubuntu-MATE 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1)'
This disc is called: 
'Ubuntu-MATE 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1)'
Copying package lists...gpgv: Signature made Tue Feb  9 19:16:16 2021 UTC
gpgv:                using RSA key 843938DF228D22F7B3742BC0D94AA3F0EFE21092
gpgv: Good signature from "Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>"

Reading Package Indexes... 0%

Reading Package Indexes... Done
Writing new source list
Source list entries for this disc are:
deb cdrom:[Ubuntu-MATE 20.04.2.0 LTS _Focal Fossa_ - Release amd64 (20210209.1)]/ focal main multiverse restricted universe
Repeat this process for the rest of the CDs in your set.