Transcript Document

Page 184 #1-5 ANSWERS
Student Progress
Learning Chart
Lesson Reflection for
Chapter 4 Section 8
Math Learning Goal
Students will
understand number
theory and fractions.
Students will understand number theory and fractions by
being able to do the following:
•
•
•
•
•
•
•
Learn to use divisibility rules (4-1)
Learn to write prime factorizations of composite numbers (4-2)
Learn to find the greatest common factor (GCF) of a set of numbers (4-3)
Learn to convert between decimals and fractions (4-4)
Learn to write equivalent fractions (4-5)
Learn to use pictures and number lines to compare and order fractions (4-6)
Learn to convert between mixed numbers and improper fractions (4-7)
• Learn to add and subtract fractions with like
denominators (4-8)
Adding and Subtracting with
4-8 Like Denominators
Today’s Learning Goal Assignment
Learn to add and
subtract fractions
with like
denominators.
Course 1
Adding and Subtracting with
4-8 Like Denominators
th
6
Grade Math HW
Page 190
#1-9
Course 1
Adding and Subtracting with
4-8 Like Denominators
Warm Up
Problem of the Day
Lesson Presentation
Course 1
Adding and Subtracting with
4-8 Like Denominators
Warm Up
Write each mixed number as an
improper fraction.
1. 6
1
__
3. 3
2
__
3
7
4
5. 9 __
5
Course 1
19
__
3
2. 2
1
__
23
__
7
4. 8
1
__
49
__
5
8
6. 4 __
5
2
11
11
__
5
17
__
2
52
__
11
Adding and Subtracting with
4-8 Like Denominators
Problem of the Day
Marge has six coins that total $1.15. She
cannot make change for $1.00, a halfdollar, a quarter, a dime, or a nickel. What
coins does she have?
half dollar, quarter, 4 dimes
Course 1
Adding and Subtracting with
4-8 Like Denominators
Today’s Learning Goal Assignment
Learn to add and
subtract fractions
with like
denominators.
Course 1
Adding and Subtracting with
4-8 Like Denominators
Additional Example 1: Application
1
Snow was falling at a rate of __ inch per hour. How
4
much snow fell after two hours? Write your answer
in simplest form.
1
__
+
1
__
4 4
1 __
1
2
__
__
+
=
4
4
4
1
__
=
2
Add the numerators. Keep the
same denominator
Write your answer in simplest terms.
+
After 2 hours
Course 1
=
1
__
2
inch of snow fell
Adding and Subtracting with
4-8 Like Denominators
Try This: Example 1
1
Rain was falling at a rate of __ inch per hour. How
8
much rain fell after two hours? Write your answer in
simplest form.
1
__
+
1
__
8 8
1 __
1
2
__
__
+
=
8
8
8
1
__
=
4
Add the numerators. Keep the
same denominator.
Write your answer in simplest terms.
+
After 2 hours
Course 1
=
1
__
8
inch of rain fell.
Adding and Subtracting with
4-8 Like Denominators
Additional Example 2A: Subtracting Like
Fractions and Mixed Numbers
Subtract. Write the answer in simplest form.
A.
3
1 – __
5
To get a common denominator, rewrite 1
as a fraction with a denominator of 5.
5 – __
3
2
__
__
=
5
5
5
Subtract the numerators. Keep the same
denominator.
―
Course 1
=
Adding and Subtracting with
4-8 Like Denominators
Additional Example 2B: Subtracting Like
Fractions and Mixed Numbers
Subtract. Write the answer in simplest form.
1
5 – 2 __
B. 5 __
12
12
5
5
1
__
– 2 __
12
4
__
3
12
1
__
3
3
12
Subtract the fractions.
Then subtract the whole numbers.
Write your answer in simplest form.
-
Course 1
=
Adding and Subtracting with
4-8 Like Denominators
Try This: Example 2A
Subtract. Write the answer in simplest form.
A.
2
1 – __
6
To get a common denominator, rewrite 1
as a fraction with a denominator of 6.
6 – __
2
4
__
__
=
Subtract the numerators. Keep the same
6
6
6
denominator.
–
Course 1
=
Adding and Subtracting with
4-8 Like Denominators
Try This: Example 2B
Subtract. Write the answer in simplest form.
7 – 2 __
4
B. 4 __
12
12
4
7
4
__
– 2 __
12
3
__
2
12
1
__
2
4
12
Subtract the fractions.
Then subtract the whole numbers.
Write your answer in simplest form.
-
Course 1
=
Adding and Subtracting with
4-8 Like Denominators
Additional Example 3A: Evaluating Expressions
with Fractions
2 . Write
Evaluate the expression for x = __
9
each answer in simplest form.
A.
5 –
__
x
9
5 –
__
x
Write the expression.
9
5 – __
2
__
9
9
=
3
__
9
2
__
Substitute
for x and subtract the
9
numerators. Keep the same denominator.
1
= __ Write your answer in simplest form.
3
Course 1
Adding and Subtracting with
4-8 Like Denominators
Additional Example 3B: Evaluating Expressions
with Fractions
2 . Write
Evaluate the expression for x = __
9
each answer in simplest form.
B.
x+2
x + 2
4
__
9
4
__
Write the expression.
9
4
6
2
__
__
__
2
2
=
+
9
9
9
= 2
Course 1
2
__
3
Substitute
2
__
for x. Add the
9
fractions. Then add the whole
numbers.
8 Write your answer in simplest
__
, or
3 form.
Adding and Subtracting with
4-8 Like Denominators
Additional Example 3C: Evaluating Expressions
with Fractions
2 . Write
Evaluate the expression for x = __
9
each answer in simplest form.
C.
8
x + __
9
x +
8
__
9
8
10
1
2
__
__
__
__
,
or
1
=
+
9
9
9
9
Course 1
Write the expression.
2
__
Substitute 9 for x and subtract
the numerators. Keep the same
denominator.
Adding and Subtracting with
4-8 Like Denominators
Try This: Example 3A
2
__
Evaluate the expression for x = 6 . Write
each answer in simplest form.
A.
4 –
__
x
6
4 –
__
x
Write the expression.
4 – __
2
2
__
__
=
2
__
Substitute 6 for x and subtract the
6
6
Course 1
6
6
numerators. Keep the same denominator.
1
= __ Write your answer in simplest form.
3
Adding and Subtracting with
4-8 Like Denominators
Try This: Example 3B
2
__
Evaluate the expression for x = 6 . Write
each answer in simplest form.
B.
x+3
x + 3
1
__
6
1
__
Write the expression.
6
1
3
2
__
__
__
3
3
=
+
6
6
6
= 3
Course 1
1
__
2
2
__
Substitute
for x and subtract
6
the numerators. Keep the same
denominator.
Write your answer in simplest
form.
Adding and Subtracting with
4-8 Like Denominators
Try This: Example 3C
2
__
Evaluate the expression for x = 6 . Write
each answer in simplest form.
C.
5
x + __
6
x +
5
__
6
5
7
1
2
__
__
__
__
,
or
1
=
+
6
6
6
6
Course 1
Write the expression.
2
__
Substitute 6 for x and subtract
the numerators. Keep the same
denominator.
Adding and Subtracting with
4-8 Like Denominators
Lesson Quiz
Add or subtract. Write each answer in
simplest form.
1. 1
9
– __
3. 2
3
__
2
__
2. 1
11 11
10
+4
1
__
10
16
4. Evaluate ___
21
8
– __
9
1
__
9
2
__
6 5
–
6.
x for x = __
21
3
__
10
__
21
5. Weston walks 4 of a mile every day. How far
will he have walked in 4 days? 3 miles
Course 1