HISTORIANS of mathematics attribute the first use of the cross x as a symbol for multiplication to William Oughtred (“Clavis Mathematicae”, London, 1631). See W. W. R. Ball's “Short Account of the ...

THIS consists simply of a gigantic multiplication table for every figure up to 100 times 160, there being 100 horizontal lines of products arranged in 160 vertical columns on a sheet 5 feet long and ...