Dividing
Decimals by Other
Decimals
Unit 3.7
Pages 126-128
Warm Up
Problems
Divide
1. 4.8 2 =
2.4
2. 16.1 7 =
2.3
3. 0.36 3 =
0.12
4. 25.28 4 =
6.32
What
Whatnumber
numberisisthe
thedividend?
quotient?
divisor?
45
76 3420
3.7 Dividing Decimals by Decimals.
Objective:
by the end of class students can
change a divisor with decimals into a whole
number and then divide into the dividend to
find the quotient.
We follow the same rules for dividing
whole numbers, as we divide numbers
with decimals in them.
015
015
5 075
5 0.75
-5
25
-2 5
-5
25
-2 5
Dividing by a Decimal Number
This time the
DIVISOR will
have a decimal
in it. We will
need to change it
into a whole
number first by
moving the
decimal to the
right side.
006
07042
-0
42
-4 2
Dividing by a Decimal Number
When we
Now
changed
we must
the
multiply
divisor tothe
a
whole
DIVIDEND
number
weby
multiplied
10 too! it
When
by 10.
weThat
do this
is
why
the decimal
the decimal
will
now
moved
move
from
to the
a
part
rightof1aspace.
whole
to a whole
x 10
006
07042
x 10
-0
42
-4 2
Find each Product
3.6 1.2
Count the total
number of decimal
places in the divisor
and move the
decimal the same
amount of spaces in
the dividend.
First divide the
equation like you
normally would.
Place the decimal
point directly above
in the quotient.
03
1.2 3.6
-0
36
-3 6
0
=3
Find each Product
7.5 1.5
Count the total
number of decimal
places in the divisor
and move the
decimal the same
amount of spaces in
the dividend.
First divide the
equation like you
normally would.
Place the decimal
point directly above
in the quotient.
05
1.5 7.5
-0
75
-7 5
0
=5
Find each Product
9.9 1.1
Count the total
number of decimal
places in the divisor
and move the
decimal the same
amount of spaces in
the dividend.
First divide the
equation like you
normally would.
Place the decimal
point directly above
in the quotient.
09
1.1 9.9
-0
99
-9 9
0
=9
Count the total
number of
decimal places in
the divisor and
move the
decimal the same
amount of spaces
in the dividend.
First divide the
equation like you
normally would.
TRY ESTIMATING
DOUBLE DIGIT
NUMBERS FIRST!
Place the decimal
point directly
above in the
quotient.
10.5 1.5
07
~20 1.5 10.5
Find each Product
-0
105
-1 0 5
0
=7
Find each Product
Count the total
number of
decimal places in
the divisor and
move the
decimal the same
amount of spaces
in the dividend.
First divide the
equation like you
normally would.
TRY ESTIMATING
DOUBLE DIGIT
NUMBERS FIRST!
Place the decimal
point directly
above in the
quotient.
20.4 5.1
~50
04
5.1 20 4
-0
204
-2 0 4
0
=4
Find each Product
Count the total
number of
decimal places in
the divisor and
move the
decimal the same
amount of spaces
in the dividend.
First divide the
equation like you
normally would.
TRY ESTIMATING
DOUBLE DIGIT
NUMBERS FIRST!
Place the decimal
point directly
above in the
quotient.
20.4 5.1
~50
04
5.1 20 4
-0
204
-2 0 4
0
=4
Let’s do a few together
#1) Find each Product
6.5 1.3
05
1.3 6.5
=5
Let’s do a few together
#2) Find each Product
20.7 0.6
34.5
=
034 5
0.6 20.70
Let’s do a few together
#3) Find each Product
25.5 1.5
17
=
017
1.5 25.5
Let’s do a few together
#4) Find each Product
5.4 0.9
6
=
06
0.9 5.4
Let’s do a few together
#5) Find each Product
2.2 13.2
6
=
06
2.2 13.2
#6) Find each Product
0264 125
0.24 63.39 000
63.39 0.24
=264.125
#7. Marcus drove 354.9 miles in 6.5 hours. On average,
how many miles per hour did he drive?
1 hr
1 hr
1 hr
1 hr
1 hr
1 hr
½
=
354.9
miles
1 hr
Marcus drove ____ miles/hours?
Homework
(3.7A) page 131-132
Due: Friday
 1-14
Dividing
by decimals
Day Two
Unit 3.7
Pages 129-132
#8. Anthony spends $87.75 on shrimp. The shrimp cost
$9.75 per pound. How many pounds of shrimp does
Anthony buy?
=
$87.75
=
1 lb $9.75
Marcus drove ____ miles/hours?
What
Whatnumber
numberisisthe
thedividend?
quotient?
divisor?
45
76 3420
*Get into groups of two or three.
*Place the number cards face
down on the desk.
*Pick up 2 cards to be your divisor
and 3 cards to be the dividend.
*Take turns placing 2 plastic chips
between each number to
represent decimals.
*Preform the division and share
your answers.
3.7 Dividing Decimals by Decimals.
Objective:
by the end of class students can
change a divisor with decimals into a whole
number and then divide into the dividend to
find the quotient using powers of 10 and
variables.
Dividing by using a variable
0.732 n
n=0.06
Substitute the
variable for the
number given.
And divide as
you would with
whole
numbers.
012 2
n 0.732
.06
-6
13
-12
12
-12
# 28 Find each quotient
73.814 c
c=1.3
Replace the variable
with the given
number.
Count the total
number of decimal
places in the dividend.
Place the decimal
point directly above
in the quotient.
Then divide the
equation like you
normally would.
56 78
1.3
c 73.814
2
# 31.
P
E
M
D
A
S
6.35 x 10 0.5
635 0.5
0.5 6350.
2
# 32.
P
E
M
D
A
S
8.1 x 10 0.9
810 0.9
0.9 8100.
Blast-Off
Question!
The PRODUCT
of the magic
squares equal
4.5 .25
3.375
In every row,
column, and
Diagonally. Fill
in the empty
squares.
0.5
Homework
(3.7B) page 131-132
Due: Monday
 27-36
49
0.7
70
38.43 6.1
3.25
Find each quotient
21.63 2.1
10.3
I spent $13.44 renting 4
videos. What was the
cost per video each?
$3.36