how to calculate serial dilutions using the hemocytometer - heocytometer (Oct/02/2010 )

hey im in my final year in biomedical science but im still a bit lost when it comes to serial dilutions. In our lab the other day I got an average of 51 cells and our dilution factor was 1/100. I used 5 large squares so the cell volume was 50000. I carried out my calculation like this:
51x50000x100, however when i looked at the notes my dmonstrator had given me it said to divide by 100 not multiply to give a result of 25.5x10power of 3 (sorry i dont know how to do the power sign on this computer lol!).
However I needed to have 2x10power3 cells/ml as my final concentration, but im completely lost:(can someone pls help!!

andrea

See the attachment in this thread http://www.protocol-online.org/forums/topic/5838-cell-counting/page__p__55266#entry55266