<?php
    $a = 10;
    ++$a; // Pre-Increment; will increase $a by one and return 11
    $a++; // Post-Increment; returns $a and then increases it by 1
    --$a; // Pre-Decrement; will decrease $a by one and return 9
    $a--; // Post-Decrement; returns $a and then decreases it by 1
?>