How can PHP beginners ensure they are working with numerical values instead of text?

PHP beginners can ensure they are working with numerical values by using the `is_numeric()` function to check if a variable contains a numeric value. This function returns true if the variable is a number or a numeric string, and false otherwise. By using this function, beginners can validate input data and avoid errors when performing mathematical operations.

$number = "42";

if (is_numeric($number)) {
    // Perform calculations or operations with $number
    echo "The number is: " . $number;
} else {
    echo "Invalid input. Please enter a numeric value.";
}