i am a rat θΔ

truly cannot envision how you would use this machine to do math

My grandfather was obsessed with calculators like this. He collected many like this before he passed away in the 1970s. I'm not that old; My other grandfather is still alive. I wonder if he was around today what he could say about these.
He taught me to care of myself, and the people I care about. But only because he didn't do those things, and he missed out on a lot.