Pages program lost when installing new SSD or when migrating new user

I installed a new, larger SSD into my old MacBook Air mid-2013 (with your help, thanks very much! :) and then followed your guide to reinstall Mac OS. I then migrated my husband from his old MacBook Pro 13" mid-2012. All went rather well, except that for some reason the Pages writing program got lost. Pages originally came with the mid2013 ( I used it all the time) but did not yet exist on his old mid-2012 from which he migrated. I can't seem to be able to reinstall it off the App Store since the mid2013 does not accept the latest Pages update.... What to do?