It would be nice to have the ability to evaluate expressions in evernote. An example of implementation is calca. I use it sometimes to keep track of some of my electronics designs where the value of some component depends on other values. It allows me to iterate through design by just changing the values of my base assumptions the rest is getting computed Automatically. The examples in the calca page show other really cool use for this like budgeting. It would be nice to have the same capability in evernote so I don't have to switch editors.