Transcript File

Multiplying by Powers of Ten
100
10
1000
10
100
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Multiplying by Powers of 10
Type
Example
Multiplying Decimals by Powers
of 10 such as 10, 100, 1000 . . .
Move the decimal point to the right
the same number of places as there
are zeros in the power of 10.
0.5 X 100 = 50
Multiplying Decimals by Powers
of 10 such as .1, .01, .001 . . .
Move the decimal point to the left
the same number of places as there
are decimal places in the power of
10.
.
Two zeros move the two places to the right!!
0.06 X 0.01 = 0.0006
.
Two decimal places move the two places to the left!!
10,000 1000 100 10' s
1' s
5 3 7
1
ths
10
1
1
ths
ths
100
1000
4 8
2
What are the
PLACE
VALUES of the
digits in this number?
10,000 1000 100 10' s
1' s
5 3 7
1
ths
10
1
1
ths
ths
100
1000
4 8
2
So that means
2
4
8
500 + 30 + 7 + 10 + 100 + 1000
10,000 1000 100 10' s
1' s
5 3 7
1
ths
10
1
1
ths
ths
100
1000
4 8
2
The decimal point
just separates the whole
numbers from the decimal
fractions
10,000 1000 100 10' s
1' s
5 3 7
1
ths
10
1
1
ths
ths
100
1000
4 8
2
What happens when I
multiply this number by
10 ?
10,000 1000 100 10' s
1' s
5 3 7
1
ths
10
1
1
ths
ths
100
1000
4 8
2
Each digits value will
become 10 times bigger so
the decimal moves one
place to the RIGHT
because there is one 0
Multiplying by 10
537.482 x 10 = 5374.82
It LOOKS like the decimal
point moves one place to
the RIGHT.
Multiplying by 10
Moving the digits one place to
the left is the same as moving
the decimal point one place to
the RIGHT.
5 3 7
4 8
2
5 3 7
4 8
2
Multiplying by 100
Moving the digits two places to
the left is the same as moving
the decimal point two places to
the RIGHT.
5 3 7
4 8
2
5 3 7
4 8
2
10,000 1000 100 10' s
1' s
2 9 4
1
ths
10
1
1
ths
ths
100
1000
1 2
5
What happens when I
multiply this number by
.1?
10,000 1000 100 10' s
1' s
2 9 4
1
ths
10
1
1
ths
ths
100
1000
1 2
5
Each digits value will
become 10 times smaller
so the decimal moves one
place to the LEFT because
there is one place value
Multiplying by 1
294 125 x 1
=
29 4125
It LOOKS like the decimal
point moves one place to
the LEFT.
Multiplying by .1
Moving the digits one place to
the right is the same as moving
the decimal point one place to
the LEFT.
2 9 4
1 2
5
2 9 4
1 2
5
Multiplying by .01
Moving the digits two places to
the right is the same as moving
the decimal point two places to
the LEFT.
2 9 4
2 9 4
1 2 5
1 2
5
Get white
boards and
markers for
your group!
Multiply:
1) 392 X 10 =
3,920
2) 392 X 100 = 39,200
3) 392 X 1000 = 392,000
4) 4.21 X 10 = 42.1
5) 4.21 X 100 = 421
6) 4.21X 1000 = 4,210
What do
you notice
about the
answers?
Multiply:
1) 89 X .1 =
2) 89 X .01 =
3) 89 X .001 =
8.9
.89
.089
4) 4.21 X 10 = 42.1
5) 4.21 X 100 = 421
6) 4.21X 1000 = 4,210
What do
you notice
about the
answers?