Decimals in a trigonometry table in Tabulae primi mobilis B by Bianchini, written in the 15th century. (Van Brummelen, Hist. Math., 2024) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In 1593, German mathematician Christopher Clavius made a small mark that would change mathematics forever. In a sine table in his treatise on the astrolabe, Astrolabium, he indicated the fractionation of a whole number by writing what has come to be regarded as the very first use of the decimal point. There is, however, just one problem. According to new painstaking research by historian Glen Van Brummelen of Trinity Western University, this wasn't, in fact, its first...