Math 5: Multiplying Fractions

Multiplying fractions is as easy as pie... and significantly easier than pi.

5th GradeMath
Elementary and Middle School5th Grade
LanguageEnglish Language

Transcript

00:30

their own numerators and denominators then we multiply the two numerators

00:34

together giving us the product's numerator and we multiply the two denominators [Dino and Coop looking at a blackboard]

00:39

together giving us the product's denominator if there are any common

00:43

factors we simplify them out and that's it. No seriously, that's it. We

00:48

know it's almost too easy like going fishing and having the fish just jump

00:52

into your boat, but hey sometimes you get lucky. Still not convinced that easy? Well,

00:57

A - how dare you call us liars and B - let's check out an example. Let's say we [Guy in Shmoop shirt looking offended]

01:01

want to find the product of three quarters and five sevenths. First we

01:05

multiply our numerators on top we've got 3 times 5 which gives us 15 next we

01:10

multiply those denominators down below we've got 4 times 7 which is 28 and

01:14

since fifteen and twenty eight share no common factors we're done. Easy as pie, or

01:20

fifteen twenty eighths of a pie good luck measuring out that slice. This [Man dances in front of pies]

01:24

method even works if we want to multiply fractions and whole numbers. Say if you want to

01:28

find the product of 5 sixths times 9 we just transform 9 into a fraction by placing

01:32

it over 1 then same ol same ol 5 times 9 is 45 and 6 times 1 is 6. 45 and 6 do

01:39

have a common factor of 3, so once we simplify that out of the numerator and [Dino and Coop looking at a blackboard]

01:43

the denominator we're left with 15 halves and we're done. Math that doesn't

01:49

require us to work on it until dawn? Sign us up! Well probably wear sweats or [Student sleeping on a couch]

01:54

something the wedding dress feels excessive..