my homework asks "use decimals and fractions in the same equation showing the commutative property, repeat for the associative property"

and my question is what do i write cause i dont know what it is?

first, review the two properties. If you don't know what they are, how can you use them? I'm sure your text has examples.

0.5 + (2/5 + 3.6) might be an example of what you want