Brand: CASIO
Model: ML-90
Type: Calculator with clock
Picture: CASIO ML-90
Batteries: GP189 x 2
Lifetime: Introduced: 1980
Terminated: unknown
Notes: Very thin calculator with touch-keys, time, alarm, and the possibility to play simple melodies and to let calculation results be played as melodies.

This particular one was bought in Dubai in 1981 by Catheleijne Berck. I even found the original bill, included here for completeness.

CASIO ML-90 bill