Halp me with this math problem... Subtracting Fractions.. 6/21

6/21-3/21=3/21

What? 6/21 is the same as 2/7. 2/7 - 1/7 = 1/7. How is this difficult?

>>17144637
I can get to that easily, but the answer in the back of the book is 1/7... How do I get to 1/7 is what I am asking...

>>17144640
>common core

Not really but the way he worded that is incredibly convoluted and makes it more difficult than it needs to be.

>>17144637
This is the right answer, you have to find a common denominator first by multiplying both the numerator and denominator (in this case, by three), after that it's simple subtraction of the numerator (never subtract the denominator)

Next time you need help with homework, please go to /wsr/

>>17144640
I never been good at math... and I still don't get the way you explained it.

Do it in steps...

you only perform the operation on the numerator once the denominators are common

so you multiply 1/7 by 3 to get a common denominator of 3/27

then you disregard the denominator when you subtract 6/27-3/27

then you reduce the result to 1/7 by dividing both the numerator and denominator by 3, reversing the first operation and simplifying it

4chan is 18+

>>17144645
The books aren't always right, this is why there are multiple editions, tell your teacher and move on.

>>17144631
3/3=1
21/3=7
1/7=1/7 is answer

3 out of 6 cats are cuddly
same thing as saying 1 out of 2 cats are cuddly
figure out the process to get from 3/6 to 1/2 and apply it to other problems

>>17144654
/27 should be /21, but you see the point

>>17144651
6 and 21 are both divisible by 3. If you divide them both by 3, you get 2/7. Then you can easily subtract 1/7 from 2/7 because they have the same denominator. That leaves you with 1/7.

>>17144655
The book is right in this instance.

Ahh I got it. I was doing it right, I just wasn't simplifying properly. Instead of dividing the 3/21 both by 3, I divided 21 by 3...

>>17144661
Oops wasn't paying attention to the answers, 3/21 = 1/7, though 3/21 may be accepted as it's basically right.

Here is another. How do I find the GCF of 192/528 to simplify that fraction?

>>17144631
So you have to find the common denominator of the two fractions first.

If you changed 1/7 into 3/21, you have
6/21 - 3/21 = 3/21

Now you have to reduce your answer to the lowest fraction it can be. 3/21 can be reduced. Divided the numerator and the denominator by 3

3 divided by 3 = 1
21 divided by 3 = 7

Your answer 3/21 has now been reduced to 1/7.