The less mixin version of making the columns can be any value as it does some math to take it to a percent. So a 6 is a 50%, so if you want a 7.5, it will just

The less mixin version of making the columns can be any value as it does some math to take it to a percent. So a 6 is a 50%, so if you want a 7.5, it will just change that to a % and then your 4.5 will fit right in. You can do this with almost every Less value bootstrap looks for. Really slick.