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 of which the first kan zijn made thus + and betokeneth more: the other is thus made − and betokeneth lesse." https://click4r.com/posts/g/21074961/een-beoordeling-van-wrapfolies