Title: Warm Up
1 Warm Up
Problem of the Day
Lesson Presentation
2Warm Up Multiply.
5 6
1.
3
23
2.
10
15
3. 0.05(2.8)
0.14
4. 0.9(16.1)
14.49
3Problem of the Day Katie made a bookshelf that
is 5 feet long. The first 6 books she put on it
took up 8 inches of shelf space. About how many
books should fit on the shelf?
45 books
4Learn to divide fractions and decimals.
5Vocabulary
reciprocal
6A number and its reciprocal have a product of 1.
To find the reciprocal of a fraction, exchange
the numerator and the denominator. Remember that
an integer can be written as a fraction with a
denominator of 1.
7Multiplication and division are inverse
operations. They undo each other.
Notice that multiplying by the reciprocal gives
the same result as dividing.
8Additional Example 1A Dividing Fractions
Divide. Write the answer in simplest form.
1 2
5 11
A.
Multiply by the reciprocal.
No common factors.
Simplest form
9Additional Example 1B Dividing Fractions
Divide. Write the answer in simplest form.
3 8
B.
2
2
Write as an improper fraction.
Multiply by the reciprocal.
No common factors
19 16 1 R 3
10Try This Example1A
Divide. Write the answer in simplest form.
7 15
3 4
A.
Multiply by the reciprocal.
No common factors.
Simplest form
11Try This Example1B
Divide. Write the answer in simplest form.
2 5
3
4
B.
Write as an improper fraction.
Multiply by the reciprocal.
No common factors.
22 15 1 R 7
12When dividing a decimal by a decimal, multiply
both numbers by a power of 10 so you can divide
by a whole number. To decide which power of 10 to
multiply by, look at the denominator. The number
of decimal places is the number of zeros to write
after 1.
1 decimal place
1 zero
13Additional Example 2 Dividing Decimals
Divide.
0.384 0.24
Divide.
14Try This Example 2
Divide.
0.585 0.25
Divide.
15Additional Example 3A Evaluating Expressions
with Fractions and Decimals
Evaluate the expression for the given value of
the variable.
5.25
A.
for n 0.15
n
Divide.
16Additional Example 3B Evaluating Expressions
with Fractions and Decimals
Evaluate the expression for the given value of
the variable.
4 5
B.
k for k 5
5
17Try This Example 3A
Evaluate the expression for the given value of
the variable.
2.55
A.
for b 0.75
b
Divide.
18Try This Example 3B
Evaluate the expression for the given value of
the variable.
4 7
B.
u , for u 9
Write as in improper fraction and multiply by the
reciprocal.
No common factors.
63 4 15 R 3
19Additional Example 4 Problem Solving Application
The number of batches of cookies you can bake is
the number of batches using the oats that you
have. List the important information
20Additional Example 4 Continued
Set up an equation.
21Additional Example 4 Continued
Let n number of batches.
22Additional Example 4 Continued
23Try This Example 4
24Try This Example 4 Continued
The number of complete trips the ship can make is
the number of trips that the ship can make with
the fuel on board. List the important information
25Try This Example 4 Continued
Set up an equation.
Amount of fuel on board
Amount of fuel for one trip
Number of trips
26Try This Example 4 Continued
Let t number of trips.
27Try This Example 4 Continued
28Lesson Quiz Part 1
Divide.
5 6
1 2
1.
2
1
2. 14 1.25
11.2
3. 3.9 0.65
6
112 x
4. Evaluate for x 6.3.
29Lesson Quiz Part 2
5.
A penny weighs 2.51 grams. How many pennies would
it take to equal one pound (453.6 grams)?
181