.chip {
  border-radius: $chip-border-radius;
  height: $chip-height;
  line-height: $chip-line-height;
  font-size: $chip-font-size;
  font-weight: $chip-font-weight;
  white-space: nowrap;
  padding-right: $chip-height / 2;

  > img {
    border-radius: $chip-border-radius;
    height: $chip-height;
    margin-right: $chip-height / 4;
    width: $chip-height;
  }

  .close {
    font-size: calc($chip-font-size + 3px);
    height: $chip-height;
    line-height: $chip-line-height;
    padding-left: calc($chip-font-size + 3px) / 2;
  }
}

.chip {
  border-radius: $chip-border-radius;
  height: $chip-height;
  line-height: $chip-line-height;
  font-size: $chip-font-size;
  font-weight: $chip-font-weight;
  white-space: nowrap;
  padding-right: $chip-height / 2;

  > img {
    border-radius: $chip-border-radius;
    height: $chip-height;
    margin-right: $chip-height / 4;
    width: $chip-height;
  }

  .close {
    font-size: calc(#{$chip-font-size} + 3px);
    height: $chip-height;
    line-height: $chip-line-height;
    padding-left: calc(#{$chip-font-size} + 3px) / 2;
  }
}

Use interpolation for variables inside calc()
Use interpolation for variables inside calc()
