$grid-tablet-columns: 4;

@for $i from 1 through ($grid-tablet-columns - 1) {
  .mdl-cell--#{$i}-offset,
  .mdl-cell--#{$i}-offset-tablet.mdl-cell--#{$i}-offset-tablet {
    @include offset-size($i, $grid-tablet-columns);
  }
}

@for $i from 1 to ($grid-tablet-columns) {
  .mdl-cell--#{$i}-offset,
  .mdl-cell--#{$i}-offset-tablet.mdl-cell--#{$i}-offset-tablet {
    @include offset-size($i, $grid-tablet-columns);
  }
}

.bar {
  content: "rows: #{$grid-tablet-columns}"
}