Casio - FX-82MS. I bought it in high school, used it in University and now on my 4th year as a Professional Accountant. Haven't changed the battery once. : r/BuyItForLife
Casio FX82MS Second Edition Scientific Calculator | School Stationery Sets | Stationery Sets | Stationery & Newsagent | Household | Shoprite ZA
Casio FX-82MS Calculator Scientific/ School Calculator two-line display with 240 Functions, Battery Powered, Colour: Dark Grey : Amazon.co.uk: Stationery & Office Supplies