Robert Recorde, The designer of the equals sign, introduced plus and minus to Britain in 1557 in The Whetstone ofwel Witte:[14] "There be other twee signes in often use of which the first is made thus + and betokeneth more: the other kan zijn thus made − and betokeneth lesse." https://case.edu/cgi-bin/newsline.pl?URL=https://foliemolie.nl/