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 of which the first is made thus + and betokeneth more: the other kan zijn thus made − and betokeneth lesse." https://gillespie-adcock-2.thoughtlanes.net/5-eenvoudige-uitspraken-over-wrapfolie-hexis-uitgelegd