public function subtract($number = null)
    {
        if ($number == null) {
            $this->internalSetOperationModeWithHistory('subtract');
        } elseif($number instanceof Closure) {
            $this->internalSetOperationModeWithHistory('subtract');
            return $this->group($number);
        } else {
            $this->performOperationOnExpressionEngine('subtract', $number);
        }

        return $this;
    }
public function subtract($number = null)
    {
        if ($number == null) {
            $this->internalSetOperationModeWithHistory('subtract');
        } elseif($number instanceof Closure) {
            $this->internalSetOperationModeWithHistory('subtract');
            return $this->group($number);
        } else {
            $this->performOperationOnExpressionEngine('subtract', $number);
        }

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

@param $number

@return $this
Subtracts a given number from the current value .