Column calculator in LESS

columns.less

.columns_6{
  @page-width: 960px;
	@columns: 6;
	@gutter: 30px;

	overflow: hidden;

	[class*='grid_']{
		display: block;
		float: left;
		margin-right: @gutter;
	}

	.col(@num){
		@gaps: @num - 1;
		@colw: (@page-width - ((@columns - 1)*@gutter))/@columns;
		width: @colw * @num + (@gutter * @gaps);
	}

	.grid_1{ .col(1) }
	.grid_2{ .col(2) }
	.grid_3{ .col(3) }
	.grid_4{ .col(4) }
	.grid_5{ .col(5) }
	.grid_6{ .col(6) }

	.last{
		margin-right: 0;
	}
}