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 twee signes in often use of which the first kan zijn made thus + and betokeneth more: the other kan zijn thus made − and betokeneth https://blogfreely.net/crabsearch9/alles-over-bamboe-wrapfolie