Is there something like "+=" in SASS?

Question

Is it possible to redefine a numerical attribute in SASS by increment or decrement? Consider something like this:

h1 {
    font-size: 10px;
}

h1.important {
    font-size: += 10px;
}

I know that I can work around that by defining a variable. Is it possible to do this without?

Answer 1

Not sure if the += works, but you could use a base variable and then add on to it in another class.

$baseFontSize: 10px

h1
  font-size: $baseFontSize


.border 
  font-size: $baseFontSize + 10px