Umgca manani ngumgca onee-integers (amanani aqhelekileyo, ...-3, -2, -1, 0, 1, 2, 3...) aya esanda ngokwanda umlibe macala omabini. U-zero (0) udla ngokuba sembindini womgca manani. Amanani anikene izithuba ezilinganayo phakathi kwawo. Amanye amanani phakathi kwamanye amanani apha kulo mgca amele amanani a-rational, a-irrational, kwanezinye iintlobo zee-real numbers.