What is the problem, really?

Problem:

 

Solution:

Not sure what you mean with the question like that, let me try to interpret it like these

$ \frac{1}{3} + 0 = \frac{1}{3} $
$ \frac{1}{3} + 3 = 3\frac{1}{3} = \frac{10}{3} $
$ \frac{1}{3} + 0.3 = \frac{19}{30} $