Transcript Dividing Decimals

Chapter 4
Decimals
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4.5
Dividing Decimals and
Order of Operations
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Dividing Decimals
Dividing decimal numbers is similar to dividing
whole numbers. The only difference is that we place
a decimal point in the quotient.
Dividing by a Whole Number
Step 1: Place the decimal point in the quotient
directly above the decimal point in the
dividend.
Step 2: Divide as with whole numbers.
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Dividing Decimals
Dividing by a Whole Number
Step 1: Place the decimal point in
the quotient directly above the
decimal point in the dividend.
Step 2: Divide as with whole
numbers.
Example
.
2 11.8
5.9
2 11.8
- 10
18
-18
0
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Example
Divide: 219.2÷8.
divisor
27.4
8 219.2
16
quotient
dividend
27.4
Check:
59

56
32
32
8
219.2
0
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Example
Divide: 0.6÷4.
divisor
0.15
4 0.60
4
quotient
dividend
0.15
Check:
20
20

4
0.60
0
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Dividing by a Decimals
If the divisor is not a whole number, before we
divide we need to move the decimal point to the
right until the divisor is a whole number.
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Example
Divide: 6.888÷2.8.
2.46
2.8 6.888
becomes
28 68.88
56
128
112
168
168
0
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Estimating When Dividing Decimals
Example:
Divide: 0.54÷12. Then estimate to whether the
proposed result is reasonable.
Exact
0.045
12 0.540
48
Estimate
60
60
0
0.05
10 0.50
 50
0
The estimate is 0.05, so 0.045 is reasonable.
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Dividing by Powers
Dividing Decimals by Powers of 10 such as 10,
100 or 1000
Move the decimal point of the dividend to the left
the same number of places there are zeros in the
power of 10.
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Example
Divide.
a. 548.6 = 0.5486
1000
b.
0.68
10
= 0.068
Move the decimal point 3 places to the left.
Move the decimal point 1 place to the left.
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Order of Operations
Order of Operations
1. Perform all operations within parentheses ( ),
brackets [ ], or other grouping symbols such as
fraction bars or square roots, starting with the
innermost set.
2. Evaluate any expressions with exponents.
3. Multiply or divide in order from left to right.
4. Add or subtract in order from left to right.
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Example
Simplify 1.4(2 – 1.8).
1.4(2  1.8)  1.4(0.2)
 0.28
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