read-only isn't via pre or post increment or decrement

[lgto4]

See ``https://www.khanacademy.org/computer-programming/when-read-only-isnt/6730568245067776 . It destroys the values of KA protected variables by pre or post incrementing or decrementing them.

[pamelafox]

Thanks for the report Bob! I'm not surprised that some new programmers attempt to decrement/increment them, given all the other creative ways they try to write programs. :)