A module for calculating mathematical expressions?

Question

PHP

Greetings.
Recommend a PHP module with which you can calculate mathematical expressions. Data is obtained from an untrusted source (user input)
Need support for internal variables. For example:

$tmp1 = 5*5+((2+7)^2)/5
$tmp2 = 3*8*$tmp1
$tmp3 = sqrt($tmp1 + $tmp2)

Answer 1

Thousands of them

Answer 2

php.net/eval