Description:
------------
Var dump fail to show right number but this number is used in memory to make calcul.


it should respect precision by cutting floating numbers
or showing the right number

Test script:
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http://3v4l.org/AFQF6

<?php
$b = 0.27*28;
$a = round($b,2);
var_dump($a-$b);

$b = 0.270000000000001;
$a = round($b,2);
var_dump($b);var_dump($a-$b);

Expected result:
----------------
float(0)
float(0.27)
float(0)

Actual result:
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float(-8.8817841970013E-16)
float(0.27)
float(-9.9920072216264E-16)