Apple Notes can evaluate calculations with variables that update as you change them.
The variable name has to be “one word,”
so usual camelCase or PascalCase will likely do you best.
I realized this while trying to calculate what height TV bench I should get:

The center of the TV should be about eye level, so what height bench should I get given myself and the sofa? Seems around 60cm will be good. Update: I realized the TV stand adds to the height of the TV bench, so it shouldn’t be part of the center of TV calculation.
[… more]