Johann Rahn
Johann Rahn ( Latinised form Rhonius ) ( 10 March 1622 – 25 May 1676 ) was a Swiss mathematician who is credited with the first use of the division sign , ÷ ( a repurposed obelus variant ) and the therefore sign , ∴ . 
<triplet> Johann Rahn <subj> 10 March 1622 <obj> date of birth <subj> 25 May 1676 <obj> date of death <triplet> obelus <subj> division sign <obj> subclass of