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View Curriculum Standards

Im ready to learn about fractions!

FRACTIONS

Basic Fractions

Comparing Fractions

Adding Fractions

Subtracting Fractions

Fraction Fun!

What are fractions?

What are fractions?

- Fractions are for counting PART of something

- The denominator tells us how many pieces

something is cut into.

- The numerator tells how many fractional pieces

there are

Basic Fractions

- A fraction is part of an entire object.

1/4 is pink

1/2 is pink

3/4 is pink

4/4 or one whole is pink

Comparing Fractions

- If the denominators of two fractions are the

same, the fraction with the largest numerator is

the larger fraction. - For example
- 5/8 is larger than 3/8
- all of the pieces are the same and
- five pieces are more than three pieces.

Comparing, cont.

Comparing Fractions, cont.

- If the numerators of two fractions are the same,

the fraction with the smaller denominator is the

larger fraction. - For example
- 5/8 is larger than 5/16
- Each fraction says there are five pieces. If an

object is divided into 8 pieces, each piece will

be larger than if the object were split into 16

pieces. Therefore five larger pieces are more

than five smaller pieces.

Adding Fractions

- Adding fractions with COMMON
- denominators is simple.
- Just add the numerators together, and place the

resulting answer in the top of a fraction and use

the existing denominator for the bottom number.

Then reduce the fraction, if possible - For example
- 3/8 2/8 5/8

Adding, cont.

Adding Fractions

- You can only add together fractions that have the

same denominator, so you must first change one or

both of the fractions so that you end up with two

fractions having a common denominator. - The easiest way to do this, is to simply select

the opposite fraction's denominator to use as a

top and bottom multiplier. - Please look at the example on the next page

Adding, cont.

Adding Fractions

- Example
- You have the fractions 2/3 and 1/4
- Select the denominator of the second fraction

(4) and multiply the top and bottom of the first

fraction (2/3) by that number - 4/4 x 2/3 8/12
- Select the denominator of the first fraction (3)

and multiply the top and bottom of the second

fraction (1/4) by that number - 3/3 x 1/4 3/12
- These two fractions (8/12 and 3/12) have common

denominators - the number 12 on the bottom of the

fraction. - Add these two new fractions together
- 8/12 3/12 11/12

Subtracting Fractions

To subtract two fractions with the same

denominator, subtract the numerators and place

that difference over the common denominator.

Look at a pizza cut into 8 pieces. Each piece is

1/8 of the pizza. Here we have 7 pieces or 7/8

of the pizza. Now take away 3/8 or 3

pieces. Were left with 4 pieces!

We just subtracted the numerators!

Subtracting, cont.

Subtracting Fractions

- To Subtract Fractions with different

denominators - Find the Lowest Common Denominator (LCD) of

the fractions - Rename the fractions to have the LCD
- Subtract the numerators of the fractions
- The difference will be the numerator and the LCD

will be - the denominator of the answer.
- Simplify the Fraction

Click here to learn more about the LCD

LCD

- To find the least common denominator, list the

multiples of each denominator (multiply by 2, 3,

4, etc.) then look for the smallest number that

appears in each list. - Example Suppose we wanted to add 1/5 1/6. We

would find the least common denominator as

follows... - First list the multiples of each denominator.
- Multiples of 5 are 10, 15, 20, 25, 30, 35, 40,...

- Multiples of 6 are 12, 18, 24, 30, 36, 42, 48,...

- Now, when you look at the list of multiples, you

can see that 30 is the smallest number that

appears in each list. - Therefore, the least common denominator of 1/5

and 1/6 is 30.

LCD, cont.

LCD

For more LCD help click here!

Fraction Fun!

If you eat 2 pieces of this pizza and your friend

eats 1 how many 10ths did you eat altogether?

If you eat 1/4 of this pizza how much will be

left?

Answer

Fraction Fun!

All the children are going to share the pizza. We

will cut enough pieces so each child can have

one, and the pieces should all be the same

size. If 7 children shared the pizza equally,

what fraction of the pizza did each child get?

Answer

Fraction Fun!

1. What fraction of the circle is shaded green?

2. What fraction of the circle is shaded red?

- What fraction would you write for the color RED?
- What fraction would you write for the color

green?

Answers

3/4 left

3/10 eaten

More Fun!

Back to Question

- 1/7

More Fun!

Back to Question

- 4/6 or 2/3
- 2/3
- 3/8
- 1/8

Back to Question

Concept Map

2005 Connecticut Mathematics Curriculum Framework

- Numerical and Proportional Reasoning

Quantitative relationships can be expressed

numerically in multiple ways in order to make

connections and simplify calculations using a

variety of strategies, tools and technologies. - How are quantitative relationships represented by

numbers?

Standards 2.1 and 2.2

- Grade 3

- 2.1
- Students should understand that a variety of

numerical representations can be used to describe

quantitative relationships. - a. Represent numbers in expanded and regrouped

forms in the base ten place value system. - b. Recognize that a fraction with the same

numerator and denominator represents the whole

object or an entire set. - c. Use fractions to measure and to represent

points on a ruler or number line. - 2.2
- Students should use numbers and their properties

to compute flexibly and fluently, and to

reasonably estimate measures and quantities - a. Use strategies that involve place value

patterns and algebraic properties to estimate,

add and subtract. - b. Approximate solutions to problems involving

computation through the use of efficient methods.

- c. Solve multiplication and division problems

using rectangular arrays, number patterns, skip

counting and repeated addends. - d. Compare fractions, identify equivalent

fractions, add and subtract fractions with like

and unlike denominators using models and

pictures.

Works Cited

- http//www.mathleague.com/help/fractions/fractions

.htmwhatisafraction - http//www.coolmath4kids.com/fractions/index.html
- http//math.rice.edu/lanius/fractions/index.html
- http//www.coolmath4kids.com/fractions/fractions-1

0-adding-with-like-denominators-01.html - http//www.superkids.com/aweb/tools/math/fraction/

commond/add.shtml