Transcript Unit 5 Multiplying Fractions

Unit 5
Multiplying Whole Numbers
by Fractions
January 10, 2013
Unit 5 Fraction Standards

MCC4.NF.4 Apply and extend
previous understandings of
multiplication to multiply a
fraction by a whole number.

MCC4.NF.4a. Understand a fraction a/b as a
multiple of 1/b.

MCC4.NF.4b. Understand a multiple of a/b as a
multiple of 1/b, and use this understanding to
multiply a fraction by a whole number.

MCC4.NF.4c. Solve word problems involving
multiplication of a fraction by a whole number, e.g.,
by using visual fraction models and equations to
represent the problem.
Visual Models
April wants to make a batch of
chocolate chip cookies and needs
1/3 cup of chocolate chips.
How can the information in the problem be represented
by a visual model?
If April makes two batches
of chocolate chip cookies,
what fraction of a cup of
chocolate chips will be needed?
If April decides to make four
batches of chocolate chip cookies,
what amount of chocolate chips
will be needed?
How can this information be
represented by an addition
equation?
By a multiplication equation?
How can a fraction model help
to show 4 x 1/3 = 1 1/3?
1/3
1/3
1/3
1/3
1/3
1/3
1/3
Each day Courtney practices guitar
for 2/3 hour. In four days, how
many hours does she practice?
How many wholes would this equal?
How can this be indicated by an addition
sentence?
Miguel fills 4 plastic cups with
orange juice. Each plastic cups
holds 5/6 cups of orange juice.
What is the total amount of
orange juice?
Build one-whole using one color
of fraction pieces.
Write the multiplication equation
 for 5 times the fraction.
5 x 4/4 =20/4=5
=
If a bucket holds 1 5/6 gallons and
5 buckets of water fill a tank,
how much water does the tank
hold?
Write the multiplication equation
and solve.
Counting Around the Class
0
1/4
2/4 3/4
4/4
1
5/4
6/4
7/4
8/4
2
Jake bought three kinds of pizza for a
party. Each pizza was the same size.
People were not hungry, and at the
end of the party there was ¾ of each
pizza left. How much pizza was left in
all?
What equation could represent this
problem?
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
1/4
3 x ¾ = 9/4
9/4 or 2 1/4
Eggs come in cartons of 12. Richard was
making cakes for a party and used 2
cartons of eggs. How many eggs did he
use?
Sabrina was making a cake for herself.
She used ¼ of a carton of eggs. There are
12 eggs in each carton. How many eggs
did she use?
Number Number Number
of
of Eggs in of Eggs
Cartons a Carton
Equation
1
2
12
24
2 x 12
2
1/4
12
3
¼ x 12
A grocery store sells bags of 9
apples. Anna used 2/3 of the
apples in a bag in an apple pie.
How many apples did she use
in the pie?
Unit 6
Fractions and Decimals
MCC4.NF.5 Express a fraction with
denominator 10 as an equivalent fraction
with denominator 100, and use this
technique to add two fractions with
respective denominators 10 and 100.
Find the tenths Decimal Square with 3 parts
shaded.
What is the fraction for the shaded
amount of the square?
Find the hundredths square with the same
amount shaded? What fraction is shaded?
Write an equation to show that these two
squares have the same amount of shading.
To make purple paint, Josh mixes
6/10 liter of red paint with 15/100
liter of blue paint. How many liters
of purple paint will he make?
Sally bought 5/10 pound of ham and
25/100 pound of turkey. How many
pounds of meat did Sally buy?
Tommy decided to mix some nuts
that he had shelled. He had 7/10
pound of walnuts and 45/100 pound
of cashews. How many pounds of
nuts did Tommy have?
MCC4.NF.6 Use decimal notation
for fractions with denominators
10 or 100.
Decimal Notation
How do you write the decimal
represented on this square?
0.8 or eight tenths
Decimal Notation
How do you write the decimal
represented on this square?
.35 or thirty-five hundredths
Relationship between decimals and
fractions
Placing decimals on a number line
.73
.5
Place the decimal .5 on the number line.
Place the decimal .73 on the number line.
Placing decimals on a number line
2.45
Place the decimal 2.45 on the number line.
Between what two numbers is the decimal 2.45?
MCC4.NF.7 Compare two decimals to
hundredths by reasoning about their size.
Recognize that comparisons are valid only
when the two decimals refer to the same
whole. Record the results of comparisons
with the symbols >, =, or <, and justify the
conclusions, e.g., by using a visual model.
Equality of Decimals
Find the tenths square that has .6
shaded. Describe the hundredths
square with the same amount
shaded and write it’s decimal.
Find the hundredths square with
45 parts shaded and write its
decimal.
We can also think of this decimal as 4
tenths and 5 hundredths, since the first
4 columns have the same amount of
shading as 4 columns on a tenths
square.
Inequality of Decimals
Select two decimal squares, write
the decimal for each, and then
write an inequality statement
using the symbols >, <.
.50 >.35