Global Variables in esphome

i want to use global variables in my .yaml-Datei and do simple calculations with them. I always get the error message:

/config/esphome/esppwm1.yaml:96:41: error: cannot convert 'float' to 'esphome::globals::RestoringGlobalsComponent<float>*' in assignment

What can I do? Can you help me please?

Did you already see this: Global Variables
And a suggestion if you still can’t solve the issue: post the yaml code that causes this error message.