Transcript Dividing Decimals by Whole Numbers

3-5 Dividing Decimals by Whole Numbers
Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes
3-5 Dividing Decimals by Whole Numbers
Warm Up
Divide.
1. 56,000 ÷ 8
7,000
2. 5,219 ÷ 17
307
3. 9,180 ÷ 12
765
3-5 Dividing Decimals by Whole Numbers
Problem of the Day
In his pocket, Bill has $0.77 made up of
10 coins. What are the coins?
1 quarter, 3 dimes, 4 nickels,
and 2 pennies
3-5 Dividing Decimals by Whole Numbers
Sunshine State Standards
MA.6.A.1.2 Multiply and divide…decimals
efficiently.
Also MA.6.A.1.1, MA.6.A.1.3
3-5 Dividing Decimals by Whole Numbers
Remember!
Quotient
0.15
5 0.75
Divisor
Dividend
3-5 Dividing Decimals by Whole Numbers
Additional Example 1A: Dividing a Decimal by a
Whole Number
Find the quotient.
0.84 ÷ 3
0.28
3 0.84
–6
24
– 24
0
Place a decimal point in the quotient
directly above the decimal point in
the dividend. Divide as you would
with whole numbers.
3-5 Dividing Decimals by Whole Numbers
Additional Example 1B: Dividing a Decimal by a
Whole Number
Find the quotient.
3.56 ÷ 4
0. 89
4 3.56
– 32
36
– 36
0
Place a decimal point in the quotient
directly above the decimal point in
the dividend. Divide as you would
with whole numbers.
3-5 Dividing Decimals by Whole Numbers
Check It Out: Example 1
Find the quotient of 2.96 ÷ 4.
0. 74
4 2.96
– 28
16
– 16
0
3-5 Dividing Decimals by Whole Numbers
Additional Example 2A: Evaluating Decimal
Expressions
Evaluate 0.936 ÷ x for the given value of x.
x=9
0.936 ÷ x
0.936 ÷ 9
0.104
9 0.936
–9
3
–0
36
– 36
0
Substitute 9 for x.
Sometimes you need to use a
zero as a placeholder.
9 > 3, so place a zero in the
quotient and divide 9 into 36.
3-5 Dividing Decimals by Whole Numbers
Additional Example 2B: Evaluating Decimal
Expressions
Evaluate 0.936 ÷ x for the given value of x.
x = 18
0.936 ÷ x
0.936 ÷ 18
0.052
18 0.936
–0
93
– 90
36
– 36
0
Substitute 18 for x.
Sometimes you need to use a
zero as a placeholder.
18 > 9, so place a zero in the
quotient and divide 18 into 93.
3-5 Dividing Decimals by Whole Numbers
Check It Out: Example 2
Evaluate 3.054 ÷ a for a = 6.
0.509
6 3.054
–30
5
–0
54
– 54
0
3-5 Dividing Decimals by Whole Numbers
Remember!
Multiplication can “undo” division. To check your
answer to a division problem, multiply the divisor
by the quotient.
3-5 Dividing Decimals by Whole Numbers
Additional Example 3: Consumer Application
Jodi and three of her friends are making a tile
design. The materials cost $10.12. If they share
the cost equally, how much should each person
pay?
$10.12 should be divided into four equal groups.
Divide $10.12 by 4.
$2. 53 Place a decimal point in the quotient
4 $10.12 directly above the decimal point in
–8
the dividend. Divide as you would
with whole numbers.
21
– 20
Check
12
2.53  4 = 10.12
– 12
Each person should pay $2.53.
0
3-5 Dividing Decimals by Whole Numbers
Check It Out: Example 3
Manuel and two of his friends went to lunch.
With tip and tax, the bill came to $25.11. The
friends agreed to split the cost equally. How
much should each person pay?
8.3 7
3 25.11
– 24
11
–9
21
– 21
0
Each person should pay $8.37.
3-5 Dividing Decimals by Whole Numbers
Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems
3-5 Dividing Decimals by Whole Numbers
Lesson Quiz
Find each quotient.
1. 3.12 ÷ 8
0.39
2. 5.68 ÷ 8
0.71
Evaluate the expression 1.25 ÷ x for the given
value of x.
3. x = 5 0.25
4. x = 25 0.05
5. The tennis team is having 3 of their tennis
rackets restrung. The total cost is $54.75. What is
the average cost per racket? $18.25
3-5 Dividing Decimals by Whole Numbers
Lesson Quiz for Student Response Systems
1. Identify the quotient.
6.84  9
A. 0.84
B. 0.76
C. 0.62
D. 0.58
3-5 Dividing Decimals by Whole Numbers
Lesson Quiz for Student Response Systems
2. Identify the quotient.
4.59  9
A. 0.51
B. 0.62
C. 0.73
D. 0.84
3-5 Dividing Decimals by Whole Numbers
Lesson Quiz for Student Response Systems
3. Evaluate the expression 1.44  x for x = 12.
A. 12
B. 1.2
C. 0.12
D. 0.012
3-5 Dividing Decimals by Whole Numbers
Lesson Quiz for Student Response Systems
4. Evaluate the expression 0.24  x for x = 12.
A. 0.4
B. 0.2
C. 0.04
D. 0.02
3-5 Dividing Decimals by Whole Numbers
Lesson Quiz for Student Response Systems
5. At a fruit stand, 8 pounds of apples cost
$2.80. Identify the average cost of apples
per pound.
A. $35.00
B. $3.50
C. $0.35
D. $0.03