Blockpad isn't just a word processor document, it also incorporates actual spreadsheets.
Insert a spreadsheet frame into your file alongside a document, like inserting a new sheet in a conventional spreadsheet.
Formulas work like in a normal spreadsheet, but with all of the Blockpad features, like units and naming values.
You can control how formulas are displayed here too, so you can show the formula and name with the result.
Reference spreadsheet cells in document equations.
It works the other way too. Use document values inside spreadsheet formulas.
Blockpad comes with a function library that has engineers in mind, like VlookupInterpolate and Interpolate2D.