Colleagues -

Prof. Hyunyong SHIN would like to share the attached article that deals with the number line as a visual representation of the real number system.


Abstract Number line is a visual representation of real number system. There was no arrow at either
end of the representation in the early figures of number line. But after the 19th century, number lines with one arrow on the right hand side have begun to appear. In USA, however, many textbooks of secondary school mathematics have number lines with arrows on the left hand side as well as on the right hand side. It is quite different from the global standard. We argue that it is mathematically reasonable for number lines to have an arrow only on the right side.

This is for your information, from

Professor Hyunyong Shin            
Department of Mathematics Education 
Korea National University of Education
Chungbuk 363-791, KOREA      

Jerry P. Becker
Dept. of Curriculum & Instruction
Southern Illinois University
625 Wham Drive
Mail Code 4610
Carbondale, IL  62901-4610
Phone:  (618) 453-4241  [O]
            (618) 457-8903  [H]
Fax:      (618) 453-4244