We can write this as:

2 19/30

We can arrive at the fraction 19/30 by recognizing .63333333 as being equal to 1.9/3. This can be determined by knowing the well know fraction 2/3=.666666 repeating. Then, you can incrementally try smaller numbers such as 1.9/3. However, this is not the simplest form. To get the simple form above, we multiplied 1.9/3 by 10/10 (equal to 1, so this is acceptable).