Arrange each sets of units in order from shortest to longest:
m,cm,mm,km
ft,mi,in,yd
Do you have a set of tables in your text or notes? For example, can you look in your tables and find 5,280 ft = 1 mile. So you know miles is a larger unit than feet. Do all of them that way. I can give you a site for m, cm, mm, and km if you need it.
Please check these sites.
http://www.aaaknow.com/mea69_x6.htm
http://www.aaaknow.com/mea69_x6.htm
http://www.aaaknow.com/mea69x12.htm