This pair of Casio watch calculators were manufactured sometime in the 1980s. They are models CA-501 and CA-502.
Vintage Casio CA-501 Digital Calculator Watch Made in Japan Mod. 437 and CA-502. The CA-501 works, I tested it summarily only but what I tested, works: set, time, calculator. Didn’t see any missing segments in the LCD. Didn’t test the alarms and other functions. The bracelet has a defect please see images. The bracelet is original.
The CA-502 does not work currently and I didn’t attempt to change the battery. The bracelet is original also and in very good condition.
Both watches are using a CR2016 slim battery.