Ace the Zend Certified PHP Engineer Challenge 2026 – Power Up Your PHP Skills!

The output of the code `echo 1 + "1.5";` is indeed 2.5. This is due to how PHP handles type juggling during arithmetic operations.

In PHP, when you perform arithmetic operations between an integer and a string that is numeric (in this case, "1.5"), PHP automatically converts the string to a number. The string "1.5" is a numerical representation that gets converted to a float during this process.

When the operation `1 + "1.5"` is executed, PHP converts "1.5" from a string to a float, resulting in the expression being evaluated as `1 + 1.5`. This computation yields 2.5. Therefore, the expected output when this result is echoed is indeed 2.5.

This behavior exemplifies PHP's dynamic typing and type juggling features, which allow it to handle operations between different data types seamlessly.