1. Factor-Label Method (of conversion)

2. The factor-label method was developed to keep track of units in multi-step conversion problems

3. Factor-label method is a method for solving problems. It is a neat and organized method that can be used in science, math, shopping, building, cooking and many other situations.

4. In life you will need to be able to switch back and forth between different units. For example- a video may be listed as 101 minutes long. You want to know how long the movie is in hours, to find out you need to do a factor label problem.

5. To solve this problem we are going to learn a generic set-up and use it to solve EVERY problem for the rest of the year. What you = what you know x the fractions you want to find need to get your answer

6. For our video problem… What you want to find = hours What you know = the movie is 101 minutes The fractions you need= 1 hour = 60 minutes

7. The set up would look like… # hours = 101 min x = 1 hour 60 min 1.68 hours

8. Make sure… Units cancel out----- This means what ever you start with is ‘on top’ and you alternate units top and bottom so they cancel out. ABCD ABC XXX= D

9. Make sure… You box your answer. I won’t know what your answer is if I cannot find it!

10. Lets try another one! Many of the problems will involve more than one step, so lets take the video problem a little further. The video is 101 minutes long, how many days long is it?

11. What we want to find = days What we know = the movie is 101 minutes Fractions we need = 1 hour = 60 minutes 1 day = 24 hours

12. # days = 101 min 1 hour 1 day 60 min 24 hr X X =0.0701 days

13. If I am driving 2 km/sec how fast am I going in miles / hour? 2 Km 1000 m 1 mi 60 sec 60 min 1 sec 1 Km 1600 m 1min 1 hr X X X X = 4500 mph

14. Try one or two with a partner!