I'd like to use the "exercise" theorem environment for exercises. However, my exercises aren't attached to specific chapters. Instead, I have "exercise series" interspersed with regular chapters, and I don't want these exercise series numbered as chapters. For example, I may have:
- Chapter 1
- Chapter 2
- Exercise Series 1
- Chapter 3
- Chapter 4
- Exercise Series 2
Is there a way I can explicitly set the chapter number for theorems, so the exercises in series 1 can be numbered 1.1, 1.2, 1.3, ... even though the "chapter" itself is unnumbered?