Exercise 1 for Lesson 2 : answers

Exercise 2 for Lesson 3 : answers

Exercise 3 for Lesson 4 : answers

Exercise 4 for Lesson 5 answers

Exercise 5 for Lesson 6 answers

Exercise 6 for Lesson 7 answers

Exercise 7 for Lesson 8 answers

Exercise 8 for Lesson 9 answers

Exercise 9 for Lesson 10 answers

Exercise 10 for Lesson 11 answers

Exercise 11 for Lesson 12 answers

Exercise 12 for Lesson 13 answers