less.js/test/css/calc.css

.no-math {
  width: calc(50% + (25vh - 20px));
  height: calc(50% + (25vh - 20px));
  min-height: calc((10vh) + calc(5vh));
  foo: 3 calc(3 + 4) 11;
  bar: calc(1 + 20%);
}
.b {
  one: calc(100% - (20px));
  two: calc(100% - (10px + 10px));
  three: calc(100% - (3 * 1));
  four: calc(100% - (3 * 1));
  nested: calc(calc(2.25rem + 2px) - 1px * 2);
}
.c {
  height: calc(100% - ((10px * 3) + (10px * 2)));
}