// Utilidad de anchuras, en fracciones: .u-1/3

$u-widths-fractions:  1 2 3 4 5 !default;

@each $denominator in $u-widths-fractions {
  @for $numerator from 1 through $denominator {
    .u-#{$numerator}\/#{$denominator} {
      width: ($numerator / $denominator) * 100% !important;
} } }