Download fraction - Pacoima Charter School

Adding Fractions
and
Mixed Numbers
(Lesson Part I adding with like
denominators of 20 or less)
Learning Objective

Today we will solve simple problems,
including ones arising in concrete
situations, involving the addition of
fractions and mixed numbers (using like
denominators of 20 or less).
concrete – solid and real
able to be seen or touched because
it exists in reality, not just an idea
Using Fractions in Every Day Life
Fractions are used in every day life situations.
A chef for example uses fractions when adding the
ingredients of a recipe to make a dish. A chef’s job
involves measuring. Most of the time, the things a chef
measures are fractional amounts like ½ teaspoon, ¾
tablespoon or 2 1/3 cups.
Have you ever measured out ingredients to make a dish or
a dessert?
Sometimes, when I cook I need to make more or less of
something than usual, so I must add, subtract, multiply, or
divide fractions to figure out the right amount to add or
delete from the recipe.
In order for the recipe to turn out right, I must understand
APK
Fractions

The word fraction means “part of a
whole.” The word comes from the Latin
word fractio, meaning “to break into
pieces.” In math, a fraction means one or
more parts of a whole or a set.
Concept Dev.
Numerators and Denominators

A fraction has two parts, a numerator and a
denominator. The denominator is the numeral
written under the bar and tells the number of
parts a whole is divided into. The numerator is
the numeral written above the bar. The
numerator tells the number of parts of the whole
that are being counted.
numerator
number of parts counted
5
denominator
total parts of a whole set
6
5
6 of the pizza is remains in the illustration on the right
Concept Dev.
•
How Important are
Fractions?
Fractions are very important when cooking. If I
don’t measure correctly or figure out just how much
of something I need to add into a mixture when I
cook, then the food I make won’t taste very good.
• Fractions are related to division.
• Fractions help you problem solve since they are
parts of a whole.
• Learning how to add fractions will help you perform
well on tests.
• Fractions relate to every day situations.
Importance
A Real-World Fraction
Problem
In a couple of weeks I will need to double my Yummy Yum
Cookies recipe in order to have enough baked cookies for
my friend’s birthday party. I will need to double the recipe
because I want to make eight dozen cookies instead of just
four.
To double the cookie recipe I will need to know
how to add, simplify, and change fractions.
In order to make the cookies turn out just right, I will have
to solve a real-world fraction problem.
Skill Dev.
Yummy Yum Cookie Recipe
To double the recipe I will need to add three different
fractions to figure out how much butter, sugar,
water, to put in.
¼ cup butter
1 cup brown sugar
1 ½ tsp vanilla
1 cup flour
1 tsp baking soda
2 ¾ cups of oats
½ cup sugar
1 egg
¾ water
Remember: A fraction is a number used to name a part of a group or a whole.
The number above the bar is the numerator, and the number below the bar is
the denominator.
Starting with Butter!


The first ingredient in the recipe is the
butter. The recipe calls for ¼ cup of
butter.
To double the amount of butter I will need
to add ¼ + ¼
Steps



First, I will look at the denominators of the
two fractions I need to add.
1 + 1
4
4
Second, if I have common denominators, then I
will add the numerators only and leave the
denominator as it .
Lastly, I will need to simplify if the fraction is not
in simplest form.
Skill Dev.
Adding Fractions
When I have a common denominator, all I have to do
is add the numerators and keep the same
denominator.
1/4 cup butter
+ 1/4 cup butter
2/4 cups butter
Skill Dev.
Simplifying the Fraction
Since both 2 and 4 can
be
divided by 2 my fraction
can be simplified.
2 ÷ 2 = 1 and 4 ÷ 2 = 2
which = ½
2/4 cups butter is simplified
as ½ a cup of butter.
Let’s try the next ingredient
with a fraction.
We need to double up ½ a cup of sugar.



First, I will look at the denominators of the
two fractions I need to add. 1 + 1
2
2
Second, if I have common denominators,
then I will add the numerators only and
leave the denominator as it .
Lastly, I will need to simplify if the fraction is
not in simplest form.
How much sugar will you need?
1 + 1
2
2 = 1 whole
You will need 1 cup of
sugar.
Let’s try the last ingredient with a
fraction; the ¾ water.




Follow the Steps.
First, look at the denominators of the
two fractions you need to add.
Second,………………..
Last,…………………….
What’s your answer?
3 +
3
6
4
4 = 4

You will need to change this improper
fraction to a mixed number.

6÷4=

4 6
=1 remainder 2

That equals 1 ½ cups of water.
Problem Solved!
Because I knew how to add, simplify, and change
fractions to I was able to double the first three
fractions ingredients in the recipe.
¼ cup shortening
½ cup sugar
¾ cup water
1/4 + 1/4 = 2/4 or 1/2 = 1/2 cup
1/2 + 1/2 = 2/2 or 1/1 = 1 cup
3/4 + 3/4 = 6/4 or 3/2 = 1 1/2 cups
1 ½ tsp vanilla
3/2 + 3/2 = 6/2 or 3/1 = 3 tsp
½ tsp baking soda
1/2 + 1/2 = 2/2 or 1/1 = 1 tsp
2 ¾ cups of oats
11/4 + 11/4 = 22/4 or 11/2 = 5 1/2 cups
Closure
Yummy Yum Cookie Recipe
Conclusion



Understanding fractions is really important,
especially when following a recipe and measuring
ingredients.
Fractions apply to real-life situations.
Knowing how to add fractions helps you make more
of a recipe, like doubling it or tripling its amount.
Closure Continued.
The End.