Error message

error evaluating function `floor`: math functions take numbers as parameters in variables.less on line 273, column 36 271| @navbar-margin-bottom: @line-height-computed; 272| @navbar-border-radius: @border-radius-base; 273| @navbar-padding-horizontal: floor(@grid-gutter-width / 2); 274| @navbar-padding-vertical: ((@navbar-height - @line-height-computed) / 2); 275| 276| @navbar-default-color: #777;