Generated by SassMeister.com, the Sass playground.

SassMeister-input.scss

// ---
// Sass (v3.2.9)
// ---


#foo {
  $width: 100px;
  width: $width;
  background-position: ($width - 20px) center;
}
 
#foo.bar {
    $width: 50px;
    background-position: ($width - 20px) center;
}

SassMeister-output.css

#foo {
  width: 100px;
  background-position: 80px center;
}

#foo.bar {
  background-position: 30px center;
}