What are common mistakes when performing calculations with PHP?

One common mistake when performing calculations with PHP is not properly handling data types. PHP automatically converts data types when performing calculations, which can lead to unexpected results. To avoid this issue, make sure to explicitly cast variables to the correct data type before performing calculations.

// Incorrect way - data types not handled properly
$num1 = "10";
$num2 = 5;
$result = $num1 + $num2; // Result will be 15 instead of 10

// Correct way - cast variables to the correct data type
$num1 = (int) "10";
$num2 = 5;
$result = $num1 + $num2; // Result will be 15