First calculator handling fractions

[Karl-Ludwig Butte]

Dear All,

which was the first calculator that could calculate with fractions? And was there a manufacturer implementing this feature before HP did? And which was the first HP model implementing this feature? By "handling fractions" I mean the ability to enter e.g 1/2 + 1/3 and getting 5/6 as result. As far as I remember, even some models with pure 7-Segment-displays were able to this, using _| as fraction line symbol.

Best regards
Karl