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." U https://bbs.pku.edu.cn/v2/jump-to.php?url=https://foliemolie.nl/