first try to analyze the problem and pick up what it is saying
Barry has 17+2/3 of his brothers basketball card so 17+2/3 is your first part
17+2/3
next if his brother has X amount of basketball cards you need to get 2/3 of the X amount
X*2/3
the put it all together
X*2/3+17 is your expression
I hope his answered your question