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 is made thus + and betokeneth more: the other is thus made − and betokeneth lesse." Dit https://posteezy.com/wrapfolienl-grondslagen-uitgelegd