Different number of columns on one page

[miafodder]

Hi all I have been searching for ages but can't find what I'm after

I want to be able to show a different number of columns on my front page

for example under the nav bar I would like 2 columns taking up 50% of the page each
below that I would like 4 columns taking up 35%, 35% 15% 15%
then three columns taking up 50% 25% 25%

[/////////] [/////////] < Row 1
[////] [////] [//] [//] < Row 2
[/////////] [///] [///] < Row 3
[/////////] [///] [///]
[/////////] [///] [///]

Hope that makes sense