How can the code snippet be optimized for better readability and understanding?

The code snippet can be optimized for better readability and understanding by using meaningful variable names, adding comments to explain the purpose of each section of the code, and formatting the code consistently. This will make it easier for other developers to understand the code and make modifications in the future.

<?php
// Initialize variables
$firstNumber = 10;
$secondNumber = 20;

// Calculate the sum of two numbers
$sum = $firstNumber + $secondNumber;

// Output the result
echo "The sum of $firstNumber and $secondNumber is: $sum";
?>