Dividing by Whole Numbers

1
Dividing by Whole Numbers

• Lesson 2-4

2
In long division, we use both multiplication and
division.
3
Key Vocabulary
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Parts of a division problem
GOES INTO
quotient
) dividend
divisor
DIVIDED BY
5
Parts of a division problem
dividend
quotient
divisor
dividend
divisor
quotient
6
Parts of a multiplication problem
factor x factor product
7
To keep your long division steps in order,
remember the basic family

• DAD
• Divide the divisor into the dividend
• MOM
• Multiply the divisor by the factor you are about
  to put into your quotient
• SISTER
• Subtract the product from the dividend/difference
• BROTHER
• Bring down the next digit in your problem
• And the CAT
• Compare your new difference with the divisor to
  make sure it is smaller
• If the difference is larger than the divisor,
  then increase the last digit in your quotient by
  one.

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Different Ways to Present the Same Problem
36 divided by 9
Divided by means that the first number is the
dividend and the second number is the divisor.
Divided into means that the first number is the
divisor and the second number is the dividend.
36 9
9 divided into 36
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Writing the Division Problem
When you are thinking about lunch I mean long
division think of In-and-Out.
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Setting up your long division problem
IN n- OUT
24 9
9
IN
OUT
11
2
Does 9 go into 24?
9 x 2 18 Subtract 24-18
9
Yes. 2 times. Put the 2 over the 4 (my last
underlined number)
-18
6
12
2
Bring the decimal point up into your answer.
9
.0
-18
6
0
We do not leave remainders when we divide
anymore. Now you need to add a decimal point to
the end of the dividend and add a zero.
13
2
6
9 x 6 54
9
.0
-18
6
0
Does 9 go into 60?
9 x 6 54
-54
6
How many times?
60 54 6
14
2
6
6
9
.0
0
-18
6
0
-54
6
0
-54
Repeat the same steps
6
15
2
6
6
9
.0
0
-18
I see that if I go one more place, I will add
another 6 to my quotient.
6
0
-54
6
0
Do you see this repeating pattern?
-54
6
16
2
6
6
6
6
6
6
6
) 24
9
.0
0
I can see that the six will keep repeating
itself. I am, therefore, going to round my answer
to the hundredths place 2.666 2.67
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How do I know where to round my answer to?

• If you are doing a problem from the book or on a
  test then read the directions for the answer to
  that question.
• If you are in a grocery store trying to figure
  out something that will cost money, round to the
  pennies place. (hundredths)
• If you see round to the nearest whole number or
  round to the nearest dollar, then round to the
  ones place.
• If your answer stops in the thousandths place, do
  not round your answer. Leave it as it is!

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What do I do if I have zeroes in my problem?
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2
7 x 2 14
7
Does 7 go into 14?
-14
Subtract 14-14 0
0
Yes. 2 times. Put the 2 over the 4 (my last
underlined number)
20
2
0
7 x 0 0
7
Does 7 go into 0 or 00?
-14
0
0
Bring down the zero
0
0
No. Put the 0 in the quotient over the 0 in the
dividend.
0 0 0
21
2
0
0
7 x 0 0
7
-14
No. Put the 0 in the quotient over the 2.
0
0
Bring down the 2
0
0
2
2 0 2
0
Does 7 go into 2?
2
22
2
0
0
7
-14
Send up the decimal point.
0
0
0
2
0
0
2
23
2
0
0
3
7 x 3 21
7
-14
0
0
Yes. 7 x 3 21. Put the 3 in the quotient over
the 5.
0
Bring down the 5
2
0
0
2
5
25 21 4
21
Does 7 go into 25?
4
24
2
0
0
6
3
7 x 6 42
7
-14
0
0
Yes. 7 x 6 42. Put the 6 in the quotient over
the 2.
0
Bring down the 2
2
0
0
25
21
Does 7 go into 42?
42 42 0
2
4
42
0
25
And the answer is
2
0
0
6
3
7
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Lets Practice
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4.302
3
28
103.6
5
29
18.09
6
30
151.08
11
31
62.301
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