On a just-now-coming-alive web page, I have two columns: change and change-percent. In the headers of the two columns, I want to give the user a small control so he can toggle between sorting the columns by abs value; and arithmetically.
In the first case, I can show him something like:
+-----+ +-----+ | ABS | or | MAG | +-----+ +-----+
What two- or three-letter abbrev can I give him to select sorting by signed value?
Or what graphics can I use to express the same ideas clearly and with good affordance?