NaN in Javasript App

Hi, Looking for help with javascript code is a wee app that I am creating for my lessons. The idea is that if you click on the blue botton you add 1 point to the score and if you click on the red button it takes a point away from the score. however when the code runs for the red dot it say “is not a number” . I hope you can help, the link to the project is below. Thanks in advance

Tappy Tap App

I can’t check for sure, but I’m guessing that it has something to do with redeclaring score inside the red dot event handler.

Thank you @beny-s , I didn’t get what you mean at first but I do now! Code is sorted now. Every day is a school day !