Math 5: Multiplying for Profit

Multiplying fractions can actually be quite useful in real life. Unfortunately, that doesn't mean you can multiply fractions of pizza to make them bigger.

5th GradeMath
Elementary and Middle School5th Grade
LanguageEnglish Language

Transcript

00:30

definitely not lunch time, them's the breaks kid. let's say Paul Pogo of Pogo's Pogo

00:35

sticks is thinking about this year's profits and yeah that's his name, poor [Paul jumping on a pogo stick]

00:39

guy never stood a chance in the trampoline business. Last year's profits

00:42

were two hundred thousand dollars and he's hoping to increase them by one

00:46

quarter this year. So how much profit will the company need to generate this

00:50

year to reach that target? And sure, a more urgent question might be whether or not

00:55

it's safe for Paul to enforce his everyone must use pogo sticks in the office at

00:59

all time policy.. but we'll leave that problem to human resources. Since we're [Workers jumping on pogo sticks fall over]

01:03

trying to figure out how to increase profit by one quarter let's first figure

01:07

out what one quarter of two hundred thousand dollars is. To do this we multiply

01:11

two hundred thousand by well.. one quarter but plot twist two hundred thousand isn't

01:16

a fraction does that mean Paul should just give up his business and start

01:19

selling frozen turkeys at the circus? Is that really Paul's backup career? Let's [Paul in a circus costume with a table of frozen turkeys]

01:23

make sure that doesn't happen, if we put a denominator of one underneath 200,000

01:28

then boom we've got ourselves a fraction and now what we've got is a couple of

01:32

fractions on our hands. We can go on fraction multiplying autopilot 200,000 [Boy holding fractions in his hands]

01:37

times one is two hundred thousand giving us a numerator of 200,000 and 1

01:41

times 4 is 4 giving us a denominator of 4, 4 happens to be a common

01:46

factor in both the numerator and the denominator and once we divide it out we

01:50

get 50,000 over one otherwise known as 50,000 does that mean we're done then

01:55

not quite, see Paul might not know everything about fractions but as a guy

02:00

in the pogo stick business he knows about things that go up and down and if [Child playing on a bungee jump]

02:04

his profits go from two hundred thousand dollars last year to 50 thousand dollars

02:07

this year that's not up that's way down and you don't need 20

02:11

years of experience making pogo sticks to see that. So what gives? Well remember

02:16

we weren't just trying to figure out what a quarter of 200,000 [Quarter coin spinning on a table]

02:19

dollars happens to be we were trying to figure out how much profit the company

02:23

will need to generate this year if it wants to make one quarter more than it

02:26

made last year, so that calls for some addition we just add $50,000

02:30

to $200,000 and there's our answer $250,000. Now all

02:35

Paul needs to do is go out there and make that money, we're sure he'll be [Paul jumps away on his pogo stick]

02:38

fine who doesn't love a good pogo stick hm, come to think of it maybe the guy at

02:43

Paul's office who needs to change the water dispenser.. [Office worker on pogo stick crashes into water dispenser]