Decimal Review:
.1 = 1/10, .01 = 1/100, .001 = 1/1000
Multiplying a decimal by a power of ten is done simply by moving the decimal point to the
RIGHT.
.0646 X 1000 = 0.0646 = 64.6
1000 has three zeros, so move the decimal point to the right 3 places.
Dividing a decimal by a power of ten is done simply by moving the decimal point to the LEFT.
Remember, division can be stated several ways.
1.07 100
1.07
100
1.07
1
100
1.07 .01
1.07
.0107
100 has 2 zeros, so move the decimal point to the LEFT 2 places.
Percent
(from the Latin, Per Centum, which means per hundred)
Percent means per one hundred equal parts. 25% means 25 per 100, or 25 out of a hundred or
25/100.
First things first:
To change a fraction to a decimal you divide the numerator by the denominator.
Example:
1
2
1 2
.5
2 1.0
.5
To change a decimal to a fraction you place the digits over the equivalent multiple of ten, then
simplify if necessary.
Examples:
0.025
From Decimal
25
1000
1
40
2
1
1.02 1
1
100 50
To Percent
To change a decimal to a percent move the
decimal point 2 places to the right (or
multiply by 100), and attach the "%" sign.
From Percent
To Decimal
To change a percent to a decimal, move the
decimal point 2 places to the left(or divide
by 100), and remove the "%" sign.
Additional Examples: (if there is no decimal point in the percent, just put one in where the %
sign is, and then move it 2 places to the left.)
1. 50% = 0.5
2. 150% = 1.5
3. 0.76% = 0.0076
To change a fraction to a percent
1. change the fraction to a decimal
2. change the decimal to a percent
To change a percent to a fraction
1. change the percent to a decimal
2. change the decimal to a fraction
Here is a table of commonly occurring values shown in Percent, Decimal and Fraction form:
Percent
Decimal
Fraction
1
/100
1%
0.01
5%
0.05
1
/20
0.1
1
/10
10%
0.125
1
/8
0.2
1
/5
0.25
1
/4
0.333...
1
/3
50%
0.5
1
/2
75%
0.75
3
/4
80%
0.8
4
/5
90%
0.9
99%
0.99
12½%
20%
25%
331/3%
9
/10
99
/100
100%
1
125%
1.25
5
/4
150%
1.5
3
/2
200%
2