Adding Three or More Fractions

Sunday, November 6, 2016




In this video you will learn to add three or more fractions with different denominators.

Transcript

Welcome to MooMooMath where we upload a ne Math video everyday. In this video I would like to work on adding more than one fraction. In particular adding three fractions. For instance, how would you add 1/2 + 1/3 + 3/4. We will start with an easy one.

I line the fractions up in a vertical line. Put 1/2 + 1/3 + 3/4 in a vertical line. I then find a common denominator for all three fractions. I know 12 will be the common denominator. I know 2 will go into 12 6 times and 6 x 1 =6 so we have 6/12. I keep them in this vertical line. 3 goes into 12 4 times and 4 x 1 = 4, and 4 goes into 12 3 times, and 3 times 9 = 9.

I next just add them up and when I add them I get 19/12

I then can convert to a mixed fraction by dividing 19 by 12 which equals 1 7/12.

Lets look at another example. Lets add 1/2 + 3/4 + 7/8

I line them up in a vertical column, and then I start thinking about a common denominator of 2.4.and 8. 8 will be the common denominator. 2 goes into 2 times, so we have 2/8's, oops 2 goes into 8 4 times.

Next 4 goes into 8 2 times and 2 times 3 = 6 and 8 goes into 8 1 time so that equals 7/8.

Next I add them, 4/8 + 6/8+7/8 = 17/8.

I have an improper fraction and 8 will go into 17 two times which is 16 and that leaves 2 1/8.

Let me go over how I created the mixed fraction.

17 divided by 8 equals 2 and 17 -16 =1 so it becomes 2 1/8

On this last one I have mixed fractions.

What if you have the following?

1 1/2 + 21/6 + 3 1/4

You can line them up vertically.

Lets line them up and you have, 1 1/2 + 2 1/6 + 3 1/4

Next you can add the whole numbers, and 1 + 2 + 3 = 6

and you will add the fractions. I'm going to rewrite them

1/2 + 1/6 + 1/4

Find a common denominator, which is 12, and 2 goes into 12 6 times, 6 goes into 12 2 times, and 4 goes into 12 3 times. I next add them up and I get 6 + 2 + 3 = 11/12

Now I combine these two and end up with 6 11/12, and I can't simplify anymore.

Thanks for watching and we upload a new Math video everyday.




Powered by Blogger.
Back to Top