**Evaluation of algebraic expressions and formulas**

**1. Evaluation of algebraic expressions**

- The process of replacing each variable with its value to find the actual value of an algebraic expression is called
**substitution**.

**2. Formulas**

- The area of a rectangle is given by
- Area = Length x Width
- A = lw

- This equality of connecting two or more variables is called a
**formula**. When the values of l and w are known, we can find the value of A in the formula by substitution.

**3. Home Work:**

- Handout: two pages
- Workbook:
- page 15: 3, 4, 5
- Page 16: 11, 12, 13
- Page 17: 14
- Page 19: 26, 27
- Page 20: 28