|Texas Instruments Math Magic.
Pressing 1 + 1 and then = will result in the bright red LED display waiting patiently for you. If you press 2, you'll be rewarded with a blinking display. If you press anything else, the calculator will tell you you're wrong with "eee." It will tell you you're wrong up to three times, and then display the correct answer for you.
So this is more of a learning tool than a calculator, but you wouldn't know that just by looking at it. If anything, it looks like a typical child's calculator. It has a color scheme that doesn't make a lot of sense and math functions that the device isn't even capable of handling, such as squares and square roots. It's weird, but Texas Instruments was going for something funky here.
TI-1000. Considering they both came out in the same year, this isn't surprising. But externally and functionally, they are very different machines.
I found this cool device at a thrift store for $2.00.