Robert Recorde, The designer of 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 is thus made − and betokeneth lesse." http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=3370392