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Fractions and Decimals Videos 17 videos
Worried about adding and subtracting fractions? Never fear. It's so easy that it will only take up a fraction of your time: just use multiplication...
Dividing Fractions 12956 Views
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Description:
Dividing fractions just means multiplying the first fraction by the reciprocal of the second fraction. But why do your fractions need dividing to begin with? Did they get in a fight?
Transcript
- 00:04
Dividing Fractions, a la Shmoop. They’ve just installed a new ride at the
- 00:09
carnival… called, "The Lunch Dispenser." All it does is flip you around for about 15
- 00:16
minutes.
- 00:17
Dividing fractions is something like this nauseating ride…
- 00:19
So how do we divide fractions? Assuming we don't have a meat cleaver handy?
Full Transcript
- 00:25
Having fractions inside fractions looks… a little unstable.
- 00:29
Instead, we try to write them with the good old division sign.
- 00:33
Since division is the opposite of multiplication…
- 00:36
…what we do is multiply the first fraction by the reciprocal of the second fraction.
- 00:43
The reciprocal just means that we switch the numerator and denominator.
- 00:47
To take the reciprocal of the second fraction simply flip five-sixths and turn it around
- 00:52
into six-fifths and we get this…
- 00:56
Basically, the top becomes the bottom and the bottom becomes the top.
- 01:00
If we have a whole number, we say that its denominator is 1.
- 01:05
So 4 is the same as 4 over 1, which means that its reciprocal is one-fourth.
- 01:11
After we've found the reciprocal of the second fraction…
- 01:13
…we can multiply the two together. 3 times 6 is 18… and 4 times 5 is 20. Giving
- 01:19
us 18 twentieths.. Don't forget to simplify your answer as much
- 01:24
as you can. The simpler the better. Dividing both sides by two gives us nine-tenths.
- 01:29
Also, remember that when dividing fractions, we only find the reciprocal of the second
- 01:35
number. Once you get used to the turns and flips,
- 01:38
dividing fractions shouldn't be too hard.
- 01:40
In fact, with all that flipping and turning, you should be ready to ride "The Lunch Dispenser."
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