CSS

sass mixin

@mixin transform($property) {
  -webkit-transform: $property;
  -ms-transform: $property;
  transform: $property;
}
.box { @include transform(rotate(30deg)); }

scss mixin

@mixin reset-list {    // Mixin without arguments
  margin: 0;
  padding: 0;
  list-style: none;
}

@mixin horizontal-list {
  @include reset-list;

  li {
    display: inline-block;
    margin: {
      left: -2px;
      right: 2em;
    }
  }
}

nav ul {
  @include horizontal-list;
}

scss mixin

@mixin rtl($property, $ltr-value, $rtl-value) { // with argumens
  #{$property}: $ltr-value;

  [dir=rtl] & {
    #{$property}: $rtl-value;
  }
}

.sidebar {
  @include rtl(float, left, right);
}

Sass @mixin and @include

@mixin important-text {
  color: red;
  font-size: 25px;
  font-weight: bold;
  border: 1px solid blue;
}