Having problem in expression designer component

Hello all, I am newbie in grasshopper and start learning from a Book called AAD. I am practicing from the screenshots given in the book, The same recipe i am using, but it shows some evaluation error can someone please help me out with this. (please download attached image for understanding my problem)

Thanks.

It’s a known issue when you are running GH in “Draw Full Names”(Display–>Draw Full Names) mode.
Check the similar topics bellow.
One way to fix this is to change your variable name from “Variable x” to “x”.

Thank you very much for the Help.:grinning::grinning:
@HS_Kim