Floats Based Column Grid

_columns.scss

// ----
// libsass (v3.1.0)
// ----

$ends: 4, 6, 8, 12;
$gutterSize: 2%;
@each $end in $ends {
  @for $i from 1 through $end {
    $single--column: (100 - (($end - 1)*$gutterSize )) / $end;
    .col-#{$i}-#{$end} {
      width: ($i*$single--column) + (($i - 1)*$gutterSize);
      @if $i == $end {
        float: none;
      } @else {
        margin-right: $gutterSize;
        float: left;
        &:last-child { margin-right: 0; }
      }
    }
  }
}