Percent of a number: Change the percent to a decimal and then multiply by the number.
Example: What is 5% of 9000. Change 5% to a decimal by moving the decimal two places to the left and dropping the percent sign. 5% becomes .05. Multiply .05 x 9000. .05 x 9000 = 450.
Percent change - The amount that a value has changed, expressed as a percentage of the original value.
Percent change = change in value x 100
original value
The percent change may be an increase or decrease. The change in value is expressed as a positive numbers.
Percent increase example:
A school with 750 pupils receives funding for an additional 75 students. What is the percent increase in funding?
Change in value = 75 increase.
Percent increase = 75 x 100
750
= 1 x 100
10
= 100
10
= 10 % increase
Percent decrease example:
One year a factory produced 60 cars per worker. The following year the factory produced 57 cars per worker. What is the percent decrease?
Change in value = 60 - 57 = 3 decrease.
Percent decrease = 3 x 100
60
= 1 x 100
20
= 100
20
= 5% decrease
Simple interest : Interest that is earned or paid only on the principal without including any earlier interest earned. The amount that earns interest does not change.
Simple interest = Principal x Rate x Time
100
Simple interest example:
If a person invests $500 at an interest rate of 4% per year, what is the amount of interest earned each year?
Simple interest = 500 x 4 x 1
100
= 2000
100
= $20 each year.
Example: What is 5% of 9000. Change 5% to a decimal by moving the decimal two places to the left and dropping the percent sign. 5% becomes .05. Multiply .05 x 9000. .05 x 9000 = 450.
Percent change - The amount that a value has changed, expressed as a percentage of the original value.
Percent change = change in value x 100
original value
The percent change may be an increase or decrease. The change in value is expressed as a positive numbers.
Percent increase example:
A school with 750 pupils receives funding for an additional 75 students. What is the percent increase in funding?
Change in value = 75 increase.
Percent increase = 75 x 100
750
= 1 x 100
10
= 100
10
= 10 % increase
Percent decrease example:
One year a factory produced 60 cars per worker. The following year the factory produced 57 cars per worker. What is the percent decrease?
Change in value = 60 - 57 = 3 decrease.
Percent decrease = 3 x 100
60
= 1 x 100
20
= 100
20
= 5% decrease
Simple interest : Interest that is earned or paid only on the principal without including any earlier interest earned. The amount that earns interest does not change.
Simple interest = Principal x Rate x Time
100
Simple interest example:
If a person invests $500 at an interest rate of 4% per year, what is the amount of interest earned each year?
Simple interest = 500 x 4 x 1
100
= 2000
100
= $20 each year.
