How to add fractions and display the result as fraction?

Question

public function add($temp) {
        $newNum = $this->num + $temp->num;
        if($this->denum == $temp->denum) {
               // add two fractions having same denominator
               $answer = $newNum . "/" . $this->denum;
        } else {
               // how to add two fractions having different denominator?
        }
        return $answer;
}

In other words, how to handle the case of two fractions having different denominators, like:

1/3 + 1/6 = 3/6

or

1/3 + 1/5 = 8/15

This question appears to be off-topic because it is about maths. — Álvaro González, Nov 26 '13 at 09:28
`$a = 1; $b = 1; $x = 3; $y = 6; //$a .'/'. $x; //$b .'/'. $y; $a = (max($x, $y) - min($x, $y))-$a; $newDivider = max($x, $y); $newNum = ($a+$b) . '/' . $newDivider; echo $newNum;` — Royal Bg, Nov 26 '13 at 09:31
@DainisAbols but I want to be display like fraction not decimal — JeraldPunx, Nov 26 '13 at 09:33
"[PHP convert decimal into fraction and back?](http://stackoverflow.com/questions/1954018/php-convert-decimal-into-fraction-and-back)" is absolutely *not* a duplicate?! — RandomSeed, Mar 08 '14 at 12:15

score 3 · Accepted Answer · answered Nov 26 '13 at 09:37

function gcd($num1, $num2) {
 /* finds the greatest common factor between two numbers */
    if ($num1 < $num2) {
        $t = $num1;
        $num1 = $num2;
        $num2 = $t;
    }
    while ($t = ($num1 % $num2) != 0) {
        $num1 = $num2;
        $num2 = $t;
    }
    return $num2;
}

public function add($temp) {
    $newNum = $this->num * $temp->denum + $temp->num * $this->denum;
    $newDenum = $temp->denum * $this->denum;
    $gcd = gcd($newNum, $newDenum);
    $newNum /= $gcd;
    $newDenum /= $gcd;
    return $newNum . '/' . $newDenum;
}

score 0 · Answer 2 · answered Nov 26 '13 at 09:27

0

Let's say you want to add 1/3 to 1/6, you simply do

$result = 1/3 + 1/6;

answered Nov 26 '13 at 09:27

DusteD

1,400
10
14

I don't think OP wants to simply calculate the result, he wants to display the formatted result, i.e. "3/6" – xlecoustillier Nov 26 '13 at 09:29
what? no need to separate the numerator and denum? – JeraldPunx Nov 26 '13 at 09:29
Numbers are numbers. You can simply display the result as a fraction if you so desire. – DusteD Nov 26 '13 at 10:05

score 0 · Answer 3 · answered Nov 26 '13 at 09:31

This won't reduce fractions for you, but other than that it should do what you want:

public function add($temp) {
    if($this->denum == $temp->denum) {
        $newNum = $this->num + $temp->num;
        $answer = $newNum . "/" . $this->denum;
    } else {
        $newNum = $this->num * $temp->denum + $temp->num * $this->denum;
        $answer = $newNum . "/" . $this->denum*$temp->denum;
    }
    return $answer;
}

How to add fractions and display the result as fraction?

3 Answers3