I seem to have forgotton how to do basic fractions I need help with a couple first one is
2/3+1 1/3*2 1/8
my work 1 1/3 * 2 1/8= 2 3/24 then I add 2 3/24+2/3 = 2 3/24 + 10/24=2 13/24 but the answer in the book is 3 1/2 so what am I doing wrong?
next is 24/5 divided by 28/15 =(24/5)*(15/28) =260/240=1 5/24 but the answer in the book says 18/7.
I am really confused any help will be greatly appreciated.

You need to get common denomiators (numbers on the bottom) Error in problem 1) 1 1/3 * 2 1/8= 2 3/24 this is false since 3/24 is 1/8 you are saying 1 1/3 * 2 1/8=2 1/8. So:
2/3 + (1 1/3*2 1/8)=
2/3 + (4/3*17/8)= <---change to mix fractions
2/3 + (68/24)=
2/3 + 17/6= <----- Reduce to lowest terms
4/6 +17/6= <------- common denominators
21/6=3 1/2 <------convert to mixed numeral

Problem 2 =(24/5)*(15/28) =260/240 is false 24*15=360 and 5*28=140
So:

24/5*15/28= <-----multiply numerators and then denominators
360/140=
36/14= <--------reduce
18/7 <------- reduce again

Thank you so much I can't believe I forgot to convert or change the mixed numbers. I don't think I will be using a calculator any more seems to give me the wrong answers.