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 ofwel which the first is made thus + and betokeneth more: the other kan zijn thus made − and betokeneth lesse." https://sparktv.net/post/277912_https-foliemolie-nl-https-nl-wikipedia-org-wiki-kwaliteit-https-foliemolie-nl-do.html