public function add($number = null)
    {
        if ($number == null) {
            $this->internalSetOperationModeWithHistory('add');
        } elseif ($number instanceof Closure) {
            $this->internalSetOperationModeWithHistory('add');
            return $this->group($number);
        } else {
            $this->performOperationOnExpressionEngine('add', $number);
        }
        return $this;
    }
public function add($number = null)
    {
        if ($number == null) {
            $this->internalSetOperationModeWithHistory('add');
        } elseif ($number instanceof Closure) {
            $this->internalSetOperationModeWithHistory('add');
            return $this->group($number);
        } else {
            $this->performOperationOnExpressionEngine('add', $number);
        }
        return $this;
    }
public function add ( $ number = null ) { if ( $ number == null ) { $ this -> internalSetOperationModeWithHistory ( 'add' ) ; } elseif ( $ number instanceof Closure ) { $ this -> internalSetOperationModeWithHistory ( 'add' ) ; return $ this -> group ( $ number ) ; } else { $ this -> performOperationOnExpressionEngine ( 'add' , $ number ) ; } return $ this ; }
Adds a given number to the current value.

@param $number

@return $this
Adds a given number to the current value .