Wait, you literally have a calculator pre-installed on your computer, yet you are trying to use a search engine to do math? Just because some search engines happens to handle some basic arithmetic functions doesn't mean all search engines necessarily support the same features.
This is why helpdesks get paid the big bucks.
I love that I can dump all my knowledge there and have it be easily searchable on my PC, phone, etc. I love that I can take notes, attach PDFs and images, or make my own canvases and excalidraw diagrams. It's awesome and flexible.
I hate that it's not FOSS. I appreciate that it's an open format (plaintext Markdown files) and prefer closed app and open data to the reverse (Joplin is open source, but mangles notes into a database). I'm strongly considering giving logseq a try, but some of my favorite obsidian features have become a crutch that I don't know if I want to live without.