Transcript 4-7

4-7 Comparing and Ordering Fractions
Learn to use pictures and number lines to
compare and order fractions.
4-7 Comparing and Ordering Fractions
Vocabulary
like fractions
unlike fractions
common denominator
4-7 Comparing and Ordering Fractions
When you are comparing fractions, first
check their denominators. When
fractions have the same denominator,
they are called like fractions. For
6
___
4
___
example, 7 and 7 are like fractions.
When two fractions have different
denominators, they are called unlike
7
___
fractions. For example, 10 and
unlike fractions.
1
___
2
are
4-7 Comparing and Ordering Fractions
Additional Example 1A: Comparing Fractions
Compare. Write <, >, or =.
6
__
4
__
7
7
6
__
7
>
4
__
7
6
__
4
__
From the model, 7 > 7 .
4-7 Comparing and Ordering Fractions
Additional Example 1B: Comparing Fractions
Compare. Write <, >, or =.
1
__
5
__
9
9
1
__
9
<
5
__
9
1
__
5
__
From the model, 9 < 9 .
4-7 Comparing and Ordering Fractions
Check It Out: Example 1A
Compare. Write <, >, or =.
4
__
_5_
6
6
4
__
6
<
5
__
6
4
__
5
__
From the model, 6 < 6 .
4-7 Comparing and Ordering Fractions
Check It Out: Example 1B
Compare. Write <, >, or =.
3
__
2
__
9
9
3
__
9
>
2
__
9
3
__
2
__
From the model, 9 > 9 .
4-7 Comparing and Ordering Fractions
To compare unlike fractions without
models, first rename the fractions so they
have the same denominator. This is called
finding a common denominator. This
method can be used to compare mixed
numbers as well.
4-7 Comparing and Ordering Fractions
Additional Example 2: Cooking Application
Ray has
2
__
3
cup of nuts. He needs
3
__
4
cup to
make cookies. Does he have enough nuts
for the recipe?
Compare
2
__
3
and
3
__
4
.
Find a common denominator by multiplying the
denominators.
3 • 4 = 12
4-7 Comparing and Ordering Fractions
Additional Example 2 Continued
Find equivalent fractions with 12 as the
denominator.
2
__
3
__
= __
3
12
2•4
______
3•4
2
__
=
8
= __
12
3
= __
4
12
8
__
12
3•3
______
9
= __
4•3
12
3
__
4
=
9
__
12
4-7 Comparing and Ordering Fractions
Additional Example 2 Continued
Compare the like fractions.
8
__
12
<
9
__
12
, so
2
__
3
<
3
__
4
.
3
2
Since __
cup is less than __ cup, he does not
3
have enough.
4
4-7 Comparing and Ordering Fractions
Check It Out: Example 2
Trevor has
1
__
3
1 cup to
cup of soil. He needs __
4
fill a small planter. Does he have enough soil
to fill the planter?
Compare
1
__
3
and
1
__
4
.
Find a common denominator by multiplying the
denominators.
3 • 4 = 12
4-7 Comparing and Ordering Fractions
Check It Out: Example 2 Continued
Find equivalent fractions with 12 as the
denominator.
1
__
= __
3
12
1
__
1•4
______
4
= __
3•4
12
1•3
______
1
__
1
__
4
= __
12
3
= __
4
12
3
= __
4•3
12
4
=
3
__
12
4-7 Comparing and Ordering Fractions
Check It Out: Example 2 Continued
Compare the like fractions.
4
__
3
__
12 > 12 , so
1
__
3 >
1
__
4 .
1
1 cup, he does have
Since __
cup is more than __
3
enough.
4
4-7 Comparing and Ordering Fractions
Additional Example 3: Ordering Fractions
Order
4 __
__
,2
5
3
, and
2• 5
_______
1
__
3
from least to greatest.
10
= __
3 • 5 15
4• 3
_______
12
= __
5• 3
15
0
1• 5
_______
5
= __
3• 5
15
5
15
10
15
12
15
1
3
2
3
4
5
Rename with like
denominators.
1
The fractions in order from least to greatest
2 , __
4 .
1 , __
are __
3
3
5
4-7 Comparing and Ordering Fractions
Remember!
Numbers increase in value as you move from left
to right on a number line.
4-7 Comparing and Ordering Fractions
Check It Out: Example 3
1
4 , __
3 , and __
Order __
from least to greatest.
7
3• 7
_______
1• 7
_______
21
= __
4 • 7 28
4• 4
_______
16
= __
7• 4
28
0
4
4
7
= __
4• 7
28
7
28
16
28
21
28
1
4
4
7
3
4
Rename with like
denominators.
1
The fractions in order from least to greatest
1
__
4
__
3
__
are 4 , 7 , 4 .