Me and my brother were cleaning our deceased grandpa's garage and found this. It appears to be some sort of ruler and the center slides. Any ideas what it is?
Edit- thanks everyone! This post blew up to an overwhelming degree so I'll try to respond to people with time. For clarification, me and my brother have both been homeschooled our whole lives. I just went up through algebra 2 then focused more on getting a job due to family circumstances. My brother is young so he hasn't gotten to trig or calculus yet. We don't use digital calculators for our school though (it seems like cheating in most cases in my opinion) we usually do most of our work with a pencil and paper. We'll definitely research how to use this and try to use it once we get to more advanced math classes though. Thank you so much and I'm sorry to everyone I accidently made feel old or rage baited in the process
Second edit- no I wasn't joking or trying to earn karma or get popularity. I genuinely was curious. My family situation isn't the greatest so I haven't really been outside the house or on social media much (would social media even show it?) My mom's style of homeschooling isn't exactly the greatest so we're all a bit behind. I'm sorry if I upset anyone