Order the numbers from least to greatest. 3 63/80, 3 1/5, 3 11/20

Let's compare apples to apples and oranges to oranges: convert each given proper fraction into its decimal counterpart:

3 63/80 = > 3.788 approx.

3 1/5 = > 3.2

3 11/20 = > 3.55

It's now an easy matter to arrange these numbers from least to greatest:

3.2, 3.55, 3.79, or

3 1/5, 3 11/20, 3 63/80