A mixin removing margins on the sides & allowing responsive adaptivity

Column mixin

@mixin columnReset($columnnb, $margewidth : 15px){
  &:nth-child(#{$columnnb}n+1) {
    margin-left: $margewidth;
  }
  &:nth-child(#{$columnnb}n+#{$columnnb}){
    margin-right: $margewidth;
  }
}

// Call this mixin like :
// @include column(4);
// For a bloc of 25% of the width (4 columns)
@mixin column($columnnb, $margewidth : 15px) {
  $marge: (($columnnb * 2 * $margewidth) - ($margewidth * 2)) / $columnnb;
  width: calc(#{100% / $columnnb} - #{$marge});
  margin-left: $margewidth;
  margin-right: $margewidth;
  @for $i from 1 through $columnnb - 1 {
    @include columnReset($i, $margewidth);
  }
  &:first-child{
    margin-left: 0;
  }
  &:nth-child(#{$columnnb}n+#{1 + $columnnb}) {
    margin-left: 0;
  }
  &:nth-child(#{$columnnb}n+#{$columnnb}){
    margin-right: 0;
  }
  &:last-child {
    margin-right: 0;
  }
}