Sat math Essentials

–
N U M B E R S A N D O P E R AT I O N S R E V I E W
–
6 1

---

P e r c e n t
A percent is a ratio that compares a number to 100. For example, 30% 
1
3
0
0
0
.
■
To convert a decimal to a percentage, move the decimal point two units to the right and add a percentage
symbol.
0.65 
65%
0.04 
4%
0.3 
30%
■
One method of converting a fraction to a percentage is to first change the fraction to a decimal (by dividing
the numerator by the denominator) and to then change the decimal to a percentage.
3
5
0.60 
60%
1
5
0.2 
20%
3
8
0.375 
37.5%
■
Another method of converting a fraction to a percentage is to, if possible, convert the fraction so that it has
a denominator of 100. The percentage is the new numerator followed by a percentage symbol.
3
5
1
6
0
0
0
60%
2
6
5
1
2
0
4
0
24%
■
To change a percentage to a decimal, move the decimal point two places to the left and eliminate the per-
centage symbol.
64% 
0.64 87% 
0.87 7% 
0.07
■
To change a percentage to a fraction, divide by 100 and reduce.
44% 
1
4
0
4
0
1
2
1
5
70% 
1
7
0
0
0
1
7
0
52% 
1
5
0
2
0
2
5
6
0
■
Keep in mind that any percentage that is 100 or greater converts to a number greater than 1, such as a whole
number or a mixed number.
500% 
5
275% 
2.75 or 2 
3
4
Here are some conversions you should be familiar with: