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## PowerPoint Slideshow about ' Real Life Fractions' - paulos

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### Real Life Fractions

http://www.ed.gov/pubs/EarlyMath/8.jpg

When do we use fractions?

- Cooking
- Measurement
- Telling time
- Money

What is a fraction?

- Fractions show part of something. Such as pieces of a pizza, part of an hour, half a pound, a quarter of an dollar.
- The top of the fraction is the numerator. It tells the pieces.
- The bottom of the fraction is the denominator. It tells how many make up a whole.

Equivalent Fractions

Sometimes we can write a fraction more than one way. If we have 4 out of 6 slices of cake left we can write our fraction two ways, because 4/6 = 2/3.

4/6 is shaded and also

2/3 is shaded.

http://www.mathleague.com/help/fractions/fractions.htm#whatisafraction

Equivalent Fractions

Look to see if the numerator and denominator have a like factor. If they do, we can simplify the fraction. Examples: 3 and 9 have like factors, so 3/9 = 1/3.

Adding Fractions

When we combine units the denominators need to bee the same. Meaning, when we add fractions, we have to have like denominators.

2 +3 = 53+ 6= 9

7 7 7 11 11 11

Common Denominators

- If you are not given like denominators, you have to find the least common denominator.
- Take your denominators, and factor them out.
- Then, match up any common denominators. Pull one factor for each match. For example 2x2=4 and 2x3=6, so pull out one 2 since there is a 2 in each.

Common Denominators

- Next, account for the numbers not matched up. So for 4 and 6, we would account for the 2 and 3 that did not match up.
- We would multiply all the numbers together. Meaning the 2 and 3, with the number we took out earlier, which was a 2.
- So from 2 x 2 =4 and 2 x 3 = 6, our denominator would be 2x2x3=12.

Find the common denominator when given these two fractions.

- 1+ 2= ?
3 9 ?

Remember your denominators are 3 and 9.

If you put 9 you are right!

3 x 1 = 3 and 3 x 3= 9

One 3 matches up, so take it out. The rest does not, so take the remaining 3 and 1 out.

3 x 3 x 1 = 9

How to change into equivalent fractions.

Once you have found your common denominator, you need to find the equivalent fractions.

1 = 3 Because we need 9 as our denominator,

3 9 we multiply 3 x 3 to get 9. What ever we multiply the denominator by, we do the same to the numerator.

If you said 9 you are correct!

3 = 9

4 12

Because 4 x 3 = 12, you have to

multiply the top by 3 also.

3 x 3 = 9

Did you get:

2 + 1 = 13

3 5 15

Why? Your denominator has to be 15, because 3 and 5 have no like factors, so multiply 3 x 5 = 15.

10 + 3= 13

15 15 15

Congratulations!

You are on your way to mastering fractions.

Works Cited

Picture on Page 1

- http://www.ed.gov/pubs/EarlyMath/8.jpg
Picture on Page 5

- http://www.mathleague.com/help/fractions/fractions.htm#whatisafraction
All other pictures clip art.

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