## Section21.2<exercisegroup>
Sometimes you have several exercises that should all have a common set of instructions, which is when you will use the <exercisegroup> tag. An <exercisegroup> can only be placed inside an <exercises> element, however! The portion of this section headed as “21.3 Exercises” is produced using the code in Listing 21.2.1.
If you want the contents of an <exercisegroup> to be put in multiple columns, you can add a @cols attribute to the <exercisegroup> of the form @cols="3". The integer value of @cols must be between 2 and 6 (inclusive).
An <exercisegroup> generates exercises in a separate section or subsection. The code in Listing 21.2.1 produces the output seen in Exercises 21.3.