This § gives you good material to practice all you learned in Ch 6 once more.
However, the final 2 exercises, that are 43 and 44, are pretty tough.
So you have a choice:
+ the Challenge path: just do §6.6 completely.
+ the Standard path:
Do: - §6.6 excluding 43 and 44,
- p.229 E7 and E8