What are the potential pitfalls of using strings as default values for numerical variables in PHP?

Using strings as default values for numerical variables in PHP can lead to unexpected behavior and errors when performing mathematical operations or comparisons. To avoid this issue, it is recommended to use numerical values as default values for numerical variables.

// Incorrect way using string as default value
$number = "10";
$result = $number + 5; // This will result in a value of 15

// Correct way using numerical value as default value
$number = 10;
$result = $number + 5; // This will result in a value of 15