Don't compare float values in PHP!

test.php

<?php

$a = 0.20;

// Test 1:

$b = 1 - 0.80; // 0.20

if ($a == $b) {
    echo "true";
}else {
    echo "false";
}
// Result: false


// Test 2:

$c = bcsub(1, 0.80, 2); // 0.20

if ($a == $c) {
    echo "true";
}else {
    echo "false";
}
// Result: true