Microscopy. Bleurgh

Hi, i did my first microscopy practical last week and im just writing up my rough work now... However, i've realised i didnt record which magnification i was using! High school error, i know..

Anyway, I was measuring the head of a hog louse..

The measurements i scribbled down say: 3 Ocular units/ 75 micrometres

I have also made a note of: 100 x 30 Stage units... (Dont even remember writing that, but it's here, so i obviously did. Dont know what it means though)

Not sure whether this is of any use, but the specimen data sheet says actual size of a hog louse is usually 4-6 mm. (Complete size, obviously, not just head size, which is what i was measuring.)

Im really not skilled at microscopy AT ALL. But it is a core module so i couldnt opt out of the class. Any attempted explanation of my ramblings would be appreciated. Thanks.