Dosage Problem.. !

Hi all, thanks for reading I have this dosing calc problem that I honestly don't think can be solved. We have to make a 90% on our dosage test to stay in the program. Well, we took our first test (we can retake once) and I made an 85%.... BECAUSE I left my calculator at home :'(!!!! And I checked over my problems... set up right, multiplied manually wrong. Anyways, so I'm practicing and practicing, even though I know how to do these, and this one just has me stumped:

"Dr's Order: Erythromycin (Ilosone) 2.5 tsp po q6h."
Label shows: 250mg per 5ml

How many mls should the nurse administer?

Correct me if I'm wrong, but I use DA to solve my problems, and I just can't find a way to cross out mgs... and there's no way to convert solids to liquid. I just don't get this question And I've typed it up exactly as it appears. Thanks!