What is the issue with rounding currency values in PHP?

When rounding currency values in PHP, it's important to remember that floating-point arithmetic can sometimes lead to unexpected results due to the way computers represent numbers. To avoid these issues, it's recommended to use the `number_format()` function with the `2` precision parameter to round currency values to two decimal places.

$amount = 10.555;
$rounded_amount = number_format($amount, 2);
echo $rounded_amount; // Output: 10.56