Ignore the waffle about ro - I hadn't checked elemental adept before chucking in my two penneth ,but The Aaron also gives a nice way of doing this via rollable tables "the way to handle this in Roll20 is by creating a Rollable Table with
the values 2345678, where each is weighted as 1, except for 2, which is
weighted 2" for a d6 obviously you would amend this to 23456. If you called the table EA6 for Elemental Adept using a d6 then the inline roll would be [[ 4t[EA6] +@{selected|intelligence_mod} ]] or if going in the damage section on attacks and spellcasting, leave out the @{selected bit and just choose INT as the attribute