H∩G={1,9} INTERSECTION OF H AND G
H∪G={1,2,3,5,6,7,9,10,11,28} UNION OF H AND G
<u>Step-by-step explanation:</u>
Step-1:  
Let H={1,2,5,7,9,10} and G={1,3,6,9,11,28} are individual set
Intersection of H and G (H∩G)  is {1,9}  Which means the COMMON ELEMENTS in both the set.
Step-2: 
Now the Union in both the set (H AND G) (H∪G) is {1,2,3,5,6,7,9,10,11,28}. 
Which means ALL THE  ELEMENTS in both set.