Originally published on zero2php.dev — part of the Zero to PHP course. View this lesson on the original site.
Arithmetic
Integers and floats participate in normal arithmetic:
<?php
declare(strict_types=1);
$a = 10;
$b = 3;
echo $a + $b, "\n";
echo $a / $b, "\n"; // float division
echo intdiv($a, $b), "\n";
Caveats
Gotcha: floating point is not exact money math—later courses address decimal libraries when needed.
Modulo: $a % $b gives remainder; useful for wrap-around logic.
Exercise
Set $a = 25 and $b = 7, then echo intdiv($a, $b) so the output is 3.
From Zero to PHP — PHP foundations: environment, syntax, and values