如何使用 PHP 內建函數進行數學運算？

$num = 12.56;
$roundedNum = round($num, 2); // 12.56

$num = 12.56;
$flooredNum = floor($num); // 12

$num = 12.56;
$ceilingNum = ceil($num); // 13

$num = -12;
$absNum = abs($num); // 12

$nums = [1, 2, 3, 4, 5];
$minNum = min($nums); // 1

$nums = [1, 2, 3, 4, 5];
$maxNum = max($nums); // 5

$num = 2;
$power = 3;
$result = pow($num, $power); // 8

$num = 16;
$sqrt = sqrt($num); // 4

$radius = 5;
$area = pi() * $radius ** 2; // 78.54

$num1 = 10;
$num2 = 20;
$average = ($num1 + $num2) / 2; // 15

$num = 12;
$isEven = ($num % 2 === 0); // true