How to rewrite an example without the use of create_function?

Question

When looking at PHP\'s create_function it says:

If you are using PHP 5.3.0 or newer a native anonymous function should be used instead.

Answer 1

$newfunc = function($a, $b) {
    return "ln($a) + ln($b) = " . log($a * $b);
}

echo $newfunc(2, M_E) . "\n";