Introduction: Dividing Fractions

looking to find out how to divide fractions?

well you've come to the right instructable

if you liked this instructable, dont forget to vote!

Step 1: The Problem

First, you gotta have a problem.

ill start it off with something easy

Step 2: Making a Reciprocal

dividing fractions is as easy as multiplying- basically because it almost IS multiplying.

what you have to do is make a reciprocal, which is flipping the fraction.

notice how the division sign changed to a multiplication sign

make sure you make the fraction on the RIGHT side the reciprocal

Step 3: And....!

Now, all you have to do is multiply from one side to the next!

its that easy!

dont forget to simplify!

Step 4: But What If...?

but what if you have mixed fractions?

easy.

make them into improper fractions!

multiply the whole number with the denominator
then add that number to the numerator, and write it out.

then, just repeat steps 1 - 3!

Step 5: Additional Worksheets...

heres a worksheet to get you started -

Comments

author
kidrock2 made it! (author)2009-07-04

My math teacher said something to help remember the process and I have never forgotten it: (yours is not to reason why, just invert and multiply) It's catchy!!

author
Ayacel made it! (author)2009-02-18

where is the = 1 comes from?

author
INSTRUCTUBAL made it! (author)INSTRUCTUBAL2009-02-18

when something is the same numerator/denominator, it becomes a "1", because a fraction is really a division problem. so 20 goes into 20 once, which makes it one.

author
tfaulk26 made it! (author)2009-01-29

What's next? Are going to see postings about multiplication table? I thought this site is for more sophisticated stuff...

author
INSTRUCTUBAL made it! (author)INSTRUCTUBAL2009-01-29

yeah, but what if your child is asking you for help? you just send them here 0.0

author
purduecer made it! (author)2009-01-28

May want to warn about inadvertent division by zero as well

author
Weissensteinburg made it! (author)2009-01-28

The phrase that my middle school teacher taught us (and I still use today) is "Keep it, Change it, Flip it." It refers to making the reciprocal, but is much easier to remember. Keep the first fraction, Change the sign to multiplication, Flip the second fraction.

author
NachoMahma made it! (author)NachoMahma2009-01-28

. I was just told to "invert and multiply." KCF would have been easier to remember.

author
INSTRUCTUBAL made it! (author)INSTRUCTUBAL2009-01-28

thats actually pretty good :P

author
xACIDITYx made it! (author)2009-01-28

Unfortunately, all your pictures you used at first (showing the problem before reciprocating) has a Multiplication sign, not a division sign.

author
INSTRUCTUBAL made it! (author)INSTRUCTUBAL2009-01-28

WOW... i am SO careless... im gonna have to fix that.

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