Jeanna has two brothers, ages 3 and 5
She is 4 years older than the sum of their ages
Sum is addition
( 3 + 5 ) + 4
The + 4 is because to find out how old Jeanna is,
You need to add her age to her brothers' ages
So 8 + 4 = 12
Jeanna is 12 years old
Hope this helps
-GoldenWolfX