Message to students:
The videos would help you to preview what you will learn in chapter 2.
Lesson 1 (Directed Numbers and Number Line)
Textbook Ch2.1 Concept of Directed Numbers (P.2.2 - 2.14)
Lesson 2 (Addition and Subtraction of Directed Numbers)
Textbook Ch2.2 Addition and Subtraction of Directed Numbers (P.2.15 - 2.29)