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.
kukho omnye umgca manani, equally valid and useful, that extends vertically through 0 (the origin) at right angles to our traditional number line and uses imaginary numbers (i). These so-called imaginary numbers extend above and below the traditional number line and are used in very real calculations in many areas of science and technology and also extend in both directions forever (into infinity).
A number line is usually drawn as a simple horizontal line. Another form is the helical number line. If the line of numbers is wrapped around a cylinder following an upward helical path, it becomes a helical number line. If the circumference of the cylinder is equal to the length occupied by ten numbers on the number line, it then becomes a decimal helical number line, and the numbers arrange themselves into columns, each number in a particular column having the same number ending.