McGraw-Hill Education Asu: Pehmeäkantinen kirja Painos: 2. painos Julkaisuvuosi: 2004, 16.12.2002 (lisätietoa) Kieli: Englanti
A number line is a line on which points correspond to numbers. Students use number lines when counting and skip counting, performing measuring activities, and adding and subtracting. Number lines are also used as the axes in coordinate graphing systems.