One way to solve this is by changing the mixed numbers to improper functions.
3 1/3 = 10/3
2 2/5 = 12/5
The next step I would take is to find a common denominator.
10/3 = 50/15
12/5 = 36/15
Now we can solve the original equation:
50/15 - 36/15 = 14/15
Since 14/15 is already simplified this is your final answer.