There seems to be a bit of confusion for when to use ex., e.g. and i.e. so here's some info to help clear it up.
E.g. is an abbreviation of the Latin phrase "exempli gratia" and stands for "for example". Ex., if used in the same context, is incorrect. Ex. is mostly used as short for exercise and used to refer to a cited example, e.g. "See ex. 3". I.e. is Latin for "id est" and means "that is" or "in other words." It is not used for listing examples but instead for clarifying statements and when you want to explain what you just said in a different way.
- The Chicago Manual of Style advises that if e.g. is used in “running text,” it should be “confined to parentheses or notes.”
- In US usage, a comma always follows the abbreviation, but in British usage, a comma after is optional.
Remember, when in doubt you can always write out "for example," or "that is."
Ex. is for exercises
E.g. is for examples
I.e. is for clarification