What are some common mistakes or oversights that could prevent the code provided from working as intended in PHP?

One common mistake that could prevent the code from working as intended is not properly initializing the `$total` variable before using it in the loop. To solve this issue, we need to initialize `$total` outside the loop to ensure it starts at 0 before adding the values from the array.

// Initialize total variable before the loop
$total = 0;

// Loop through the array and sum up the values
foreach ($numbers as $number) {
    $total += $number;
}

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