How do you get the answer 3/8 when you take 1/2 to the second power plus 1/2 to the third power?

Question

I am trying to study algebra before my class begins on the 7th of Oct. The book I am using says the answer to this problem is 3/8. I keep working it and I get the answer 1/32 if I multiply or 2/12 if I add. I do not understand how they got this answer,The book does not show the work, just the correct answers.

Answer 1

(1/2)^2=1/4 . . . (1/2)^3=1/8 . . . (1/4)+(1/8)=3/8...........