Why does ((1 + 2 + $var1) * $var2) / 2 - 5 equal 7 in PHP?

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simy202
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I'm going through a php tutorial right now and this math example below is driving me nuts. The exmaple was "((1 + 2 + $var1) * $var2) / 2 - 5", and all the rest of the code below is just me trying to figure it out.

The answer ends up being "7", but to me it looks like PHP is sayding "24 / -3 = 7" when it should be "24 / -3 = -8". What am I missing in this http://www.phpkode.com/scripts/category/php-math/" issue?? Thanks!

PHP:
<?php
$var1 = 3;
$var2 = 4;
?>
    $var1 = 3;<br />
        $var2 = 4;<br /><br />
       <br />
       <h1> ((1  + 2 + $var1) * $var2) / 2 - 5 = <?php echo((1  + 2 + $var1) * $var2) / 2 - 5; ?><br /> </h1>
    <hr />
    <br />
    <br />
    LEFT SIDE:<br />
    (1  + 2 + $var1) * $var2 =  <?php echo ((1  + 2 + $var1) * $var2); ?><br />
<br />
RIGHT SIDE:<br />
2 - 5 =   <?php echo 2 - 5; ?><br />
    <br />
    24 / -3 SHOULD BE:
    <h1>24 / -3 = <?php echo 24 / -3; ?><br /></h1>

That spits out:

$var1 = 3;
$var2 = 4;

((1 + 2 + $var1) * $var2) / 2 - 5 = 7

LEFT SIDE:
(1 + 2 + $var1) * $var2 = 24

RIGHT SIDE:
2 - 5 = -3

24 / -3 SHOULD BE:
24 / -3 = -8
 
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Try:
<?php echo((1 + 2 + $var1) * $var2) / (2 - 5); ?>