1. WARM UP 1.Do ACT Prep Passage B – Stickleback Fish. Start when the bell rings.

2. Mathematical Expressions

3. Units Numbers need units to be meaningful –14 ???? grams, pounds, kilograms, tons?

4. Formulas One unit is determined by a mathematical operation using two (or more) other units –area = l x w –d = m/v –e = mc 2

5. Formulas You can rearrange the equation to solve for an unknown unit –w = area / l –m = dv –m = e / c 2

6. Practice

7. Factor – Label Method Allows you to convert from one unit to another –Miles to feet –m to km

8. Factor – Label Method Need a conversion factor that represents how the two units are related –1 mile = 5,280 feet –1 km = 1,000 m

9. Factor – Label Method Conversion Process 1.Write known number, with unit, as a fraction 244 rolls 1

10. Factor – Label Method Conversion Process 1.…. 2.Write conversion factor as a fraction, with desired unit on top 244 rolls 1 dozen rolls 1 12 rolls

11. Factor – Label Method Conversion Process 1.… 2.… 3.Multiply the fractions and cancel the units 1.244 rolls 1 dozen rolls 1 12 rolls x

12. Practice

13. WRAP UP Give one reason units are important. Use the factor-label method to convert 19 quarts into gallons.