Robert Recorde, The designer ofwel the equals sign, introduced plus and minus to Britain in 1557 in The Whetstone of Witte:[14] "There be other 2 signes in often use ofwel which the first kan zijn made thus + and betokeneth more: the other kan zijn thus made − and betokeneth http://hikvisiondb.webcam/index.php?title=kornumcole0734