Transcript Long Division Can Be Easy!

DMSCB
What is DMSB? You wonder?
This stands for the order of long division
Divide
Multiply
Subtract
Compare
Bring Down
Take a look at this division problem:
This is the divisor.
The divisor is the
number of groups we
are dividing into or
the number we are
dividing by.
3 )75
This is the
dividend.
The dividend
is the number
we break into
groups.
Looks scary, huh? Well, when you use
DMSCB It can be simple. Move to
the next slide to get started!
DIVIDE
First, we want to
DIVIDE.
Ask yourself: “How
many times can 3
go into 7?”
3 )75
Think of your
multiplication
facts:
Or, draw
an array:
3x1=3
3x2=6
3x3=9
OOO
OOO
OOO
DIVIDE
You want to find the
closest number to 7
without going over!
Think of
your
multiplicatio
In this case it’s 2 times n facts:
because 3 x 2 is 6
3x1=3
3 times is too high since 3 x 2 = 6
3x3=9
3x3=9
Or, draw an
array:
OOO
OOO
OOO
DIVIDE
Now, place your 2 above the 7, because 3
goes into 7 two times.
2
3 )75
The 2 becomes
the first part of
your quotient.
The quotient is
the answer in
division.
You’ve just completed the divide. Now, we’ll
move onto multiply.
MULTIPLY
Next, you want to multiply 3 times 2:
3 x 2= 6
2
3 )75
6
We do this because we said that 3 can go into 7 two
times, but now we have to find out how close to 7
we can get. So we multiply!
MULTIPLY
That was a really simple step!
Now, we want to move on to subtract!
SUBTRACT
Now that we know how many times 3 goes into 7,
we have to subtract to see the difference
between the numbers:
2
3 )75
-6
1
Good! We know 7 – 6 = 1. Leave your 1 in it’s
spot, because we’re going to use it for the
bring down!
Compare
But before we bring down we have to compare:
2
3 )75
-6
1
Check to make sure the difference you got
when you subtracted is less than the divisor.
1 is less than 3, so now we’ll move on to bring
down.
BRING DOWN
When you bring down, you’re moving the
second part of your dividend into your
workspace:
2
3 )75
-6
15
Wow! You’ve just completed every step of
DMSCB! But, wait! There’s more!
2
3 )75
-6
15
We now have a new number
and we
have to start all over again…
DIVIDE
First, we want to
DIVIDE.
Ask yourself: “How
many times can 3 go
into 15?”
2
3 )75
-6
15
Think of your
multiplication
facts:
3x1=3
3x2=6
3x3=9
3 x 4 = 12
3 x 5 = 15
Or, draw an
array:
OO
OO
OO
OO
OO
O
O
O
O
O
DIVIDE
You want to find the
closest number to 15
without going over!
In this case it’s 5 times
because 3 x 5 is 15
Think of your Or, draw an
multiplication array:
facts:
3x
3x
3x
3x
3x
1=3
2=6
3=9
4 = 12
5 = 15
OO
OO
OO
OO
O
O
O
O
DIVIDE
Now, place your 5 above the 5, because 3 goes into
15 five times.
25
3 )74
-6
15
The 5 becomes
the second part
of your quotient.
You’re almost
done!
You’ve just completed the divide. Now, we’ll move
onto multiply.
MULTIPLY
Next, you want to multiply 3 times 5:
25
3 )75
-6
15
3 x 5 = 15
15
We do this because we said that 3 can go into 15
five times.
MULTIPLY
That was a really simple step!
Now, we want to move on to subtract!
SUBTRACT
Now that we know how many times 3 goes into 15, we
have to subtract to see the difference between the
numbers:
25
3 )75
-6
15
-15
0
Good! We know 15-15=0. Let’s compare.
Compare
Now we have to compare:
25
3 )75
-6
15
-15
0
0 is less than the divisor 3. Yeah, let’s move on!
BRING DOWN
When you bring down, you’re moving the next part of your
dividend into your workspace:
25
3 )75 ?
-6
15
-15
0?
But wait!! There’s nothing to bring down!! This is OK! You
have no more numbers in your dividend to add to your
workspace so you’re almost done! If there was a third
number in our dividend, then we would start DMSCB all over
again! You want to keep going until you have nothing to
bring down.
Here is what your division problem should
look like:
25
3 )75
-6
15
-15
0
• DMSCB is the order of operations for division. It
stands for Divide, Multiply, Subtract, Compare,
Bring Down
• The divisor the number we are dividing by. In 2)81
2 is the divisor.
• The dividend is the number we are dividing, or
breaking into groups. In 2)81 81 is the dividend
• The quotient is the answer in division.
• Remember! You want to keep going until
you have nothing to bring down.
Do It Yourself!
Now, try these problems on your own! Remember
DMSCB. When you’re finished, move to the next
slide to check your answers!
5)60
2)78
7)91
4)48
Check Yourself!
12
5)60
-5
10
-10
0
39
2)78
-6
18
-18
0
13
7)92
-7
21
-21
0
12
4)48
-4
08
-8
0
You did a really awesome job with
DMSCB. Remember! Long division
can be easy! And when you need a
little help just think of DMSCB:
Divide
Multiply
Subtract
Compare
Bring Down