The number 50 is the total sum of the 10 skills.
The number 35 (the first number in parentheses) is the sum of the outside skills, this is: is the sum of Jump Shot + Jump Range + Outside Def. + Handling + Driving + Passing.
The number 15 (the second number in parentheses) is the sum of the inside skills, this is: is the sum of Inside Shot + Inside Def. + Rebounding + Shot Blocking.
Hope you understand it!!