public function add(Number $addend)
    {
        $resultDecimalValue = $this->decimalValue() + $addend->decimalValue();

        $result = new Number($resultDecimalValue);

        return $result->convert($this->getNumberSystem());
    }
public function add(Number $addend)
    {
        $resultDecimalValue = $this->decimalValue() + $addend->decimalValue();

        $result = new Number($resultDecimalValue);

        return $result->convert($this->getNumberSystem());
    }
public function add ( Number $ addend ) { $ resultDecimalValue = $ this -> decimalValue ( ) + $ addend -> decimalValue ( ) ; $ result = new Number ( $ resultDecimalValue ) ; return $ result -> convert ( $ this -> getNumberSystem ( ) ) ; }
Add two number together.
The number-system of the result will be the one of the number
who's was the called object.

@param Number|Number $addend

@return Number
Add two number together . The number - system of the result will be the one of the number who s was the called object .