William Oughtred

William Oughtred 5 March 1574 – 30 June 1660) was an English mathematician and Anglican clergyman. 
John Napier invented logarithms and Edmund Gunter created the logarithmic scales. Oughtred was the first to use two such scales. He slid one next to another to do direct multiplication and division. He is credited with inventing the slide rule in about 1622. 
He also introduced the "×" multiplication sign and the abbreviations "sin" and "cos" for the sine and cosine functions.