How do I find out what each mark represent on a number line?

Answer 1

Doesn't that depend on what you're studying?

Inches
Feet
Yards
Millimeters
Centimeters
Meters
or ??
whole units of something
whole and fraction units of something

http://ww2.coastal.edu/kingw/psycstats/mathreview/reviewfiles/images/number_line1.gif

from http://www.google.com/search?q=number+line&es_sm=119&tbm=isch&tbo=u&source=univ&sa=X&ved=0CB4QsARqFQoTCILb283Tt8cCFUsWkgodFYYNGw&biw=1440&bih=718#imgrc=Lp4FRYYI-xhXyM%3A