To determine the ratio of full tables to empty tables at Larry's Italian Restaurant, we start by identifying the numbers given in the problem:
- Full tables: 5
- Empty tables: 6
The ratio of full tables to empty tables can be expressed as:
\[ \text{Ratio} = \frac{\text{Number of full tables}}{\text{Number of empty tables}} = \frac{5}{6} \]
Thus, the ratio of the number of full tables to the number of empty tables is 5:6.