5000 Most-Used Shorthand Forms

I have been working hard to learn the Gregg Shorthand Anniversary Edition forms for about a month or two.  I looked in the back and front of 5000 M.U.S.F. (subject title) to find out what 1-ing, 2-ing, or 5-ing means (for example on page 1).   Does anybody know?

(by i-gmail for everyone)