How does PHP evaluate expressions within curly braces in this context?

When PHP encounters curly braces within a string, it treats them as a way to evaluate expressions and insert the result into the string. To ensure that PHP evaluates expressions within curly braces correctly, you need to enclose the entire expression in curly braces, including any variables or functions. This ensures that PHP interprets the entire expression as a single unit to be evaluated.

// Example of correctly evaluating expressions within curly braces
$variable = 10;
echo "The value of the variable is {$variable}";