Robert Recorde, The designer of 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://sparktv.net/post/277764_https-foliemolie-nl-https-foliemolie-nl-zodra-je-alsnog-nooit-eerder-folie-hebt.html