Xml portfolio

I’ve got it all working fine but I’m not sure how to manipulate these lines of code to change the rows spacing of the thumbnails. Can someone help me out?

currentThumb_mc.[COLOR=#0000ff]_x[/COLOR] = COLOR=#000000[/COLOR]*thumb_spacing;
currentThumb_mc.[COLOR=#0000ff]_y[/COLOR] = [COLOR=#0000ff]Math[/COLOR].[COLOR=#0000ff]floor[/COLOR]COLOR=#000000[/COLOR]*thumb_spacing;

Missmetz