How can variables be effectively passed into and utilized within PHP functions to ensure accurate calculations?

To effectively pass variables into and utilize them within PHP functions for accurate calculations, you can define parameters in the function declaration and then pass the variables when calling the function. This ensures that the function operates on the specific values provided, leading to accurate calculations.

function calculate_sum($num1, $num2) {
    return $num1 + $num2;
}

$number1 = 5;
$number2 = 10;

$result = calculate_sum($number1, $number2);
echo "The sum of $number1 and $number2 is: $result";