Take a look at the sentence again:
Syed finally decided to clean out his disorganized book bag, old US Government
handouts, math notes from Intermediate Algebra,
leaky ballpoint pens, and a smashed banana littered the inside.
Old US Government handouts is one item in a series of four. Math notes from Intermediate Algebra is the second item in the series. You need a comma to separate one item from the other.
Go back to the sentence to try again.