奇怪的php bug例子！怎么了？

Question

<?php

$var1 = 34;// Also for 444, 460 and others
$var2 = 34;// Also for 444, 460 and others

$test = $var2/($var1/100);

var_dump($test); //float(100) 

var_dump((int)$test); //int(99)

var_dump(number_format($test, 0, '','')); //"100"

每个号码都不会发生此错误，例如33,35等。

您怎么看？