Are there any common pitfalls to avoid when working with multiple variables and calculating their sum in PHP?

One common pitfall when working with multiple variables and calculating their sum in PHP is forgetting to initialize the sum variable before adding values to it. This can lead to unexpected results or errors in the calculation. To avoid this, always initialize the sum variable to 0 before starting the calculation.

// Initialize sum variable
$sum = 0;

// Variables to sum
$num1 = 10;
$num2 = 20;
$num3 = 30;

// Calculate sum
$sum = $num1 + $num2 + $num3;

// Output the sum
echo "The sum is: " . $sum;