Transcript Comparing Fractions and Decimals by: April Ferrell

Comparing
Fractions and Decimals
Warm Up
• Order these fractions from greatest to least.
• 1.
• 2.
1 5 2 7
, , ,
2 8 9 12
5 7 1 2
, , ,
8 12 2 9
3 4 10 7
, , ,
4 20 25 8
7 3 10 4
, , ,
8 4 25 20
Warm UP
• Mary used a 12x12 grid to represent 1 and Janet
used a 10x10 grid to represent 1. Each girl shaded
¼. How many grid squares did Mary shade? How
many grid squares did Janet shade? Why did they
need to shade different numbers of grid squares?
(Use the grids on the 1st page of the hand-out)
Warm Up
• Order these fraction from least to
greatest.
1. 3
2
7
4 , 5 , 20
2. 6
1
4
10 , 2 , 5
Lesson Objectives
• 4.NF.2 Compare fractions and decimals to
the thousandths place.
• Essential Question: How can you compare
decimals and fractions?
Vocabulary Words
•
•
•
•
Least common denominator
Least common multiple
Equivalent
Decimal
Definitions
• Least common denominator is the lowest
common multiple of the denominators. The
smallest number into which both of the
denominators will divide exactly.
• Least common multiple is the smallest
number that is the multiple of two of more
numbers.
• Equivalent fractions are fractions with the
same value.
• Decimal is a number in a number system
based on 10, also known as the base 10
system.
Let’s Review
• Comparing fractions
• Comparing decimals
Comparing Fractions
• In order to compare fractions, the
denominators for each fraction
need to be the same.
• Find the Least Common Multiple
• Make equivalent fractions
Comparing Fractions
3
2
7
4 , 5 , 20
4: 4, 8, 12, 16, 20
5: 5, 10, 15, 20, 25
20: 20
LCM = 20
Comparing Fractions
3
4
=
15
20
2
5
=
8
20
7
20
=
7
20
Now order these fractions from
least to greatest.
7
20
2
5
3
4
Comparing Fractions
Order these fractions
6
10
1
2
1
2
4
5
6
10
4
5
Comparing Decimals
• When comparing decimals, you have to
look at the whole numbers.
• If the whole numbers are the same,
then look at the decimal in the tenths
place.
• Keep looking at the digits until you can
identify which is the greatest or least.
Comparing Decimals
Practice Time! Order from least to greatest
Problems
Answers
1.134, 1.341, 1.103
1.103, 1.134, 1.341
14.072, 14.172, 14.07
14.07, 14.072, 14.172
3.963, 3.63, 3.93
3.63, 3.93, 3.963
Converting Fractions to Decimals
Think about how you say the fraction.
6
= .6
10
How many TENTHS are
there? The 6 goes in the
TENTHS place.
8
=
100
.08
How many HUNDREDTHS
are there? The 8 goes in the
HUNDREDTHS place.
Converting Fractions to Decimals
If the denominator is not a tenth or
hundredth, you will need to make an
equivalent fraction using a 10 or 100
as the denominator.
4
5
=
8
=
.8
10
Converting Fractions to Decimals
3
4
Let’s try a few!
75
= 100 = .75
4
20
=
= .20
20
100
10
40
.40
=
=
25
100
Converting Decimals to Fractions
• Converting decimals to fractions is the
opposite of converting fractions to
decimals.
• Once again, read the fraction.
• What do you hear?
Tenths or hundredths?
Converting Decimals to Fractions
Think about how you say the decimal.
6
=
.6
10
8
.08 = 100
Read the decimal. The 6 is
in the TENTHS place, so
the denominator is 10.
What place is the 8 in? The
HUNDREDTHS place. The
denominator is 100.
Converting Decimals to fractions
.60
Let’s try a few!
6
60
= 10 or 100
16
.16 =
100
40
4
.40 = 100 or 10
Comparing
Fractions and Decimals
In order to compare fractions
and decimals, you have to use all
of the skills you have learned and
reviewed in this session. You can
not compare fractions and
decimals. You have to convert
them all to either fractions or all
to decimals.
Comparing
Fractions and Decimals
Compare and order these fractions and decimals.
.60
4
10
4
20
1
2
.75
.4