Casio FX82 calculator I bought in 1982 at the age of 15. Used it throughout school, my apprenticeship and work as a draughtsman. Don't use it much now but it still works
VINTAGE CASIO FX-15 Scientific Calculator with case & box Made in Japan Tested | eBay
Casio レトロ 電卓 fx-15 アンティーク-
Casio FX-991ES Plus Scientific Calculator Fx 991 Es - New & Sealed ship to world wide : Office Products - Amazon.com
Casio | Other | Casio Fx15 Es Natural Display Calculator | Poshmark
Casio FX-300ES Plus 2nd Edition Scientific Calculator, 16-Digit LCD, Blue (300ESPLS2BU) | OfficeCrave.com