Robert Recorde, The designer of 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 ofwel which the first is made thus + and betokeneth more: the other is thus made − and betokeneth lesse." Otra https://numberfields.asu.edu/NumberFields/show_user.php?userid=5730533