Robert Recorde, The designer ofwel 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 ofwel which the first is made thus + and betokeneth more: the other kan zijn thus made − and betokeneth lesse." https://sparktv.net/post/277836_https-foliemolie-nl-https-foliemolie-nl-zodra-je-nog-nimmer-eerder-folie-hebt-aa.html