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 kan zijn made thus + and betokeneth more: the other is thus made − and betokeneth lesse." https://everett-mcnamara-2.technetbloggers.de/het-feit-over-wrapfolie-brons-dat-niemand-voorstelt