Robert Recorde, The designer ofwel the equals sign, introduced plus and minus to Britain in 1557 in The Whetstone of Witte:[14] "There be other twee signes in often use ofwel which the first is made thus + and betokeneth more: the other kan zijn thus made − and betokeneth lesse." https://www.woorips.vic.edu.au/profile/kahnjwdlundberg82334/profile