Transcript 5-4 - Mr. C. Street

5-4 Regrouping to Subtract Mixed Numbers
Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes
5-4 Regrouping to Subtract Mixed Numbers
Warm Up
Add or subtract.
1.
3.
5
2.
11
__ 4.
6
20
9
__
8
11
2
__
5
9
5-4 Regrouping to Subtract Mixed Numbers
Problem of the Day
Complete the magic square so that
every row, column, and diagonal has
the same sum.
1
7
5
1
__
__
__
1__
2
2
8
8
4
1
1
5
__
__
1 __
1
12
4
8
7
__
8
3
1
3
__
__
__
1 4 1 1 8 18
3
3
1
__
__
__
2
2
8
4
8
5-4 Regrouping to Subtract Mixed Numbers
Learn to regroup mixed numbers to
subtract.
5-4 Regrouping to Subtract Mixed Numbers
3
Jimmy and his mother planted a tree when it was 1__ ft
4
1
tall. Now the tree is 2 __ ft tall. How much has the tree
4
grown since it was planted?
The difference in the heights can be represented by
1
3
__
__
2 4 – 1 4.
1
__
You will need to regroup 2 4 because the fraction
3
1
__
__
in 1
is greater than
.
4
4
1
Divide one whole of 2 __ into fourths.
4
5-4 Regrouping to Subtract Mixed Numbers
1
1
1
1
1
5
1
__
4 Regroup 2
as 1 __ .
4
4
1 1 1 1 1
4 4 4 4 4
1 1 1
4 4 4
1 1
4 4
1
__
2
4
3
–1 __
4
______
5
1 __
4
3
– 1__
4
______
1
2
__
= __
2
4
1
The tree has grown __ ft since it was planted.
2
5-4 Regrouping to Subtract Mixed Numbers
Additional Example 1A: Regrouping Mixed
Numbers
Subtract. Write each answer in simplest form.
2
__
6–3
3
Estimate the difference.
6–4=2
6
2
–3 __
3
______
2
3
5 __
3
2
–3 __
3
______
1
2 __
3
Write 6 as a mixed number with a
3 .
denominator of 3. Rename 6 as 5 + __
3
Subtract the fractions and then the
whole numbers.
1
__
is close to the estimate of 2. The answer is reasonable.
3
5-4 Regrouping to Subtract Mixed Numbers
Additional Example 1B: Regrouping Mixed
Numbers
Subtract. Write each answer in simplest form.
3
4
1
5 __
– 2 __
3
Estimate the difference.
5–3=2
4
5 __
12
16
4 __
12
9
–2 __
12
______
9
–2 __
12
______
7
2 __
12
The LCM of 4 and 3 is 12.
4
4
12
4
Rename 5 __ as 4 + 1 __= 4 + __ + __ .
12
12
12 12
Subtract the fractions and then the
whole numbers.
7
2 __ is close to the estimate of 2. The answer is reasonable.
12
5-4 Regrouping to Subtract Mixed Numbers
Check It Out: Example 1A
Subtract. Write each answer in simplest form.
1
5
__
__
7
–2
6
6
Estimate the difference.
7–3=4
1
7 __
6
7
6 __
6
5
–2 __
6
______
5
–2 __
6
______
Rename 7
1
__
6
1
1 = 6 + __
as 6 + 1__
+ __.
6
6
6
6
Subtract the fractions and then the
whole numbers.
2
1
4 __ = 4 __ Write the answer in simplest
6
3 form.
1
__
4
is close to the estimate of 4. The answer is reasonable.
3
5-4 Regrouping to Subtract Mixed Numbers
Check It Out: Example 1B
Subtract. Write each answer in simplest form.
2
7
8 __ – 6 __
5
10
Estimate the difference.
8–7=1
4
8 __
10
7
–6 __
10
______
10 is a multiple of 5, so 10 is
common denominator.
4
4 =7+
__
7
__
__
Rename
8
as
7
+
1
–6
10
10
10
______
14
7 __
10
7
1 __
10
a
4
10
__ + __
.
10 10
Subtract the fractions and then the
whole numbers.
7
__
1
is close to the estimate of 1. The answer is reasonable.
10
5-4 Regrouping to Subtract Mixed Numbers
Additional Example 2A: Measurement Application
Li is making a quilt. She needs 15 yards of fabric.
Li has 2
3
__
yards of fabric. How many more yards does
4
she need?
4
14 __ Write 15 as a mixed number with a
4
4 denominator of 4. Rename 15 as 14 + __ .
15
3
–2 __
4
______
3 Subtract the fractions and then the
–2 __
4 whole numbers.
______
1
__
12
4
Li needs another 12
1
__
yards of fabric.
4
4
5-4 Regrouping to Subtract Mixed Numbers
Additional Example 2B: Measurement Application
1
__
If Li uses 11
yards of fabric, how much of the 15
6
yards will she have left?
15
1
__
–11
6
______
6
14 __ Write 15 as a mixed number with a
6
6 denominator of 6. Rename 15 as 14 + __
.
6
1
__
Subtract the fractions and then the
–11
6 whole numbers.
______
5
__
3
6
Li will have 3
5
__
yards of fabric.
6
5-4 Regrouping to Subtract Mixed Numbers
Check It Out: Example 2A
Peggy is making curtains. She needs 13 yards of fabric.
5
__
Peggy has 4 6 yards of fabric. How many more yards
does she need?
13
5
–4 __
6
______
6
12 __
6
5
–4 __
6
______
Write 13 as a mixed number with a
6
__
denominator of 6. Rename 13 as 12 +
.
6
Subtract the fractions and then the
whole numbers.
1
__
8
6
Peggy needs another 8
1
__
yards of fabric.
6
5-4 Regrouping to Subtract Mixed Numbers
Check It Out: Example 2B
1
__
If Peggy uses 9
yards of fabric, how much of the 13
4
yards will she have left?
13
1
–9 __
4
______
4
12 __ Write 13 as a mixed number with a
4
4 denominator of 4. Rename 13 as 12 + __ .
1 Subtract the fractions and then the
–9 __
4 whole numbers.
______
3
__
3
4
Peggy will have 3
3
__
yards of fabric left.
4
4
5-4 Regrouping to Subtract Mixed Numbers
Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems
5-4 Regrouping to Subtract Mixed Numbers
Lesson Quiz
Subtract. Write each answer in simplest form.
1.
5
__
3
7
2.
3.
1
7
__
9
4.
4
9
__
10
13
5 __
16
5. Irena put 10 cups of food in the bird feeder. The birds ate
3
__
3
cups.
How many cups are left?
8
5 cups
6 __
8
5-4 Regrouping to Subtract Mixed Numbers
Lesson Quiz for Student Response Systems
1. Subtract and identify the answer in
simplest form.
A.
C.
B.
D.
5-4 Regrouping to Subtract Mixed Numbers
Lesson Quiz for Student Response Systems
2. Subtract and identify the answer in
simplest form.
A.
C.
B.
D.
5-4 Regrouping to Subtract Mixed Numbers
Lesson Quiz for Student Response Systems
3. Subtract and identify the answer in
simplest form.
A.
C.
B.
D.
5-4 Regrouping to Subtract Mixed Numbers
Lesson Quiz for Student Response Systems
4. A Dachshund weighs
pounds. A Dandi
Dinmont Terrier weighs 18 pounds. What is
the difference, in pounds, in their weights?
A.
C.
B.
D.