Which property is BEST to use when combining 3/5 + 1/4 + 2/5

Step-by-step explanation:

Commutative property of addition: The order in which you add these fractions together doesn't matter.

I would combine 3/5 and 2/5 first, as that readily results in 5/5, or just 1.

Then we have 1 1/4, or 1.25, or 5/4 as the final answer.