Transcript Long Division Can Be Easy!

DMSB
What is DMSB? You wonder?
This stands for the order of long division
Divide
Multiply
Subtract
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 )74
This is the
dividend.
The dividend
is the number
we break into
groups.
Looks scary, huh? Well, when you use
DMSB 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 )74
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 )74
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 )74
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 )74
-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!
BRING DOWN
When you bring down, you’re moving the
second part of your dividend into your
workspace:
2
3 )74
-6
14
BRING DOWN
Wow! You’ve just completed every step of
DMSB! But, wait! There’s more!
2
3 )74
-6
14
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 14?”
2
3 )74
-6
14
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 14
without going over!
In this case it’s 4 times
because 3 x 4 is 12
5 times is too high since
3 x 5 = 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 4 above the 4, because 3 goes into
14 four times.
24
3 )74
-6
14
The 4 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 4:
24
3 )74
-6
14
3 x 4 = 12
12
We do this because we said that 3 can go into 14
four times, but now we have to find out how close
to 14 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 14, we
have to subtract to see the difference between the
numbers:
24
3 )74
-6
14
-12
2
Good! We know 14-12 = 2. Leave your 2 in it’s spot,
because we’re going to use it for the bring down!
BRING DOWN
When you bring down, you’re moving the next part of your
dividend into your workspace:
24
3 )74 ?
-6
14
-12
2?
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 DMSB all over
again! You want to keep going until you have nothing to
bring down.
REMAINDER
The remainder is what you have left over (or what is
remaining) after you have nothing to bring down:
24
3 )74
-6
14
-12
2
R-2
In this problem, the remainder is 2 because 14-12 = 2. Write
your remainder next to your answer.
Here is what your division problem should
look like:
24 R - 2
3 )74
-6
14
-12
2
• DMSB is the order of operations for
division. It stands for Divide, Multiply,
Subtract, Bring Down
• The divisor is the number of groups we are
dividing into or the number we are dividing
by. In 2)81 2 is the divisor.
• The dividend is the number we break 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
DMSB. When you’re finished, move to the next
slide to check your answers!
5)62
2)78
7)92
4)45
Check Yourself!
12 r 2
5)62
-5
12
-10
2
39 r 0
2)78
-6
18
-18
0
13 r 1
7)92
-7
22
-21
1
11 r 1
4)45
-4
05
-4
1
You did a really awesome job with
DMSB. Remember! Long division
can be easy! And when you need a
little help just think of DMSB:
Divide
Multiply
Subtract
Bring Down