Simple grid functions

gistfile1.scss

@function grid-calc($n, $g: 12) {
  @return ($n / $g) * 100%;
}

// 12 column grid

@for $i from 1 through 12 {
  %grid-#{$i}-of-12 { width: grid-calc($i); }
}

// Usage <div class="grid-3-of-12"></div>
// Or @extend .grid-3-of-12