2. Unit Conversions Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) First identify the desired quantity. # km

3. Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) Next write down the starting quantity… the starting point of calculations. 47 mi

4. Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) Now we have to choose a conversion factor 47 mi

5. Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) What conversion factors are possible? 47 mi 1 km 0.621 mi 1 km

6. Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) Pick the one that will allow you to cancel out miles 47 mi 1 km 0.621 mi 1 km

7. Pick the one that will allow you to cancel out miles Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) 47 mi 1 km 0.621 mi 1 km

8. Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) Cross out common factors 47 mi x 1 km 0.621 mi

9. Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) Now finish the math. 47 x 1 km 0.621 = 75.7 km

10. Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles) The final answer is 75.7 km 47 x 1 km 0.621 = 75.7 km

11. Summary The previous problem was not that hard In other words, you probably could have done it faster using a different method However, for harder problems the factor label method is easiest

12. More examples 1.You want to buy 100 U.S. dollars. If the exchange rate is 1 Can$ = 0.65 US$, how much will it cost? 100 US$ x 1 Can$ 0.65 US$ = 153.85 Can$

13. 3.There are 12 inches in a foot, 0.394 inches in a centimeter, and 3 feet in a yard. How many cm are in one yard? 1 ydx 3 ft 1 yd = 91.37 cm x 12 in 1 ft x 1 cm 0.394 in