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 of which the first kan zijn made thus + and betokeneth more: the other kan zijn thus made − and betokeneth https://www.saludcapital.gov.co/sitios/VigilanciaSaludPublica/Lists/Contactenos/DispForm.aspx?ID=2972663