Burroughs was one of the pioneers of adding machines, beginning in the late 19th century. But this was a knock-off of a competitor's product, Felt & Tarrant's Comptometer. Burroughs called theirs a "calculator."
It came out in 1920. They made versions of these for decades, though I don't know how long this particular model ran; I assume it's from the 1920s or 30s.
This is a non-listing machine, which means that it doesn't run a tape. There's a digital readout [sic] on the front panel. What you do is crank the lever to set the readout to zero, then start typing in your numbers. As you do, the readout updates with the running total. Once you're done, you write it down, then clear it for the next run.
So it was literally an adding machine, but you can also subtract (using 9s compliments), multiply and divide with it, by way of some tricks you have to learn to do. You could use on a sales counter, but where it really lives is in the back office, where Bob Cratchit uses it to add and balance accounts in the ledger books. If you get good at it, you can fly with this thing.
Mine was jammed when I got it (aren't they all?), but it turned out to be easily opened. There's a hole in the front for what I presume is a clock key, and if you turn it, you can move the spring-loaded latch, whereby the calculator's cover swings up like the hood on a car. If you undo the screws on the back side corners, the cover comes off completely.
I poked and prodded a little and managed to clear the jam. The drums were sluggish and slow as I typed, and it jammed another couple times, but limbered up with use and now seems to work fine. I'll take the cover back off soon and take some photos.
My machine still has remnants of the Burroughs logo both on front and back, though they're black. If you light it properly you can still make it out. I don't know whether the gold letting was rubbed off or was cleaned off, or whether it was painted over. There could be a bunch of other reasons, but in the absence of any other evidence I'll go with this one: I'm relatively close to Hollywood, and movies and TV shows love to obscure brand logos unless they're specifically paid to show them. And it's not just Coke and Pepsi. I was watching Kolchak: The Night Stalker the other day and someone stuck a piece of tape over the Royal logo on his typewriter. So it's very, very possible that this was a film or tv show prop, and the logos were obscured to make the suits happy.
The thing I like best about this machine is the look—it's got octagonal keys, so it pairs nicely with my Oliver typewriter.
The Internet Archive has the operator's manual for it, which I recommend, and a brochure for their product line of the early 1920s, and a few other things.
Internet Archive has manuals and a brochure