There are 50 states in the U.S. so to find the states that don't have a store operator by company A you must subtract the states that do by the total number of states:
50 - 38 = 12
12 stores do not have a store operator by company A
To find the fraction you must do

Part is the number of states that don't have a store operator by company A
Whole is the total number of states in the U.S.
You get the fraction:

^^^This fraction can be simplified to...

Hope this helped!
~Just a girl in love with Shawn Mendes