you ask someone
You cannot. The starting value must be positive for a percentage change to make sense.
devide 9 by 12
You do not. Percentage change (increase or decrease) makes sense only if both numbers are positive or both are negative. Consider the change from -50 to +50. You could calculate the percentage change as 100*(new-old)/old = -200% Now consider the percentage change from +50 to -50. -200% again! So, in percentage terms a change from +50 to -50 is the same as from -50 to +50.
Real GDP/Capita
(New salary - old salary)/(old salary) * 100 = percent change For example, if salary changes from 100,000 to 110,000, the percentage change is (110,000 - 100,000)/(100,000) * 100 = 10%
You calculate the change in percentage points. Thus, the change from -5% to 7% is a change (increase) of 12 percentage points.Do not try to calculate it as a percentage change. The change from -50 to 50 is 100*100/(-50) works out as -200% while the change from 50 to -50 is 100*(-100)/50 = -200%. One goes up, the other goes down but the % change is the same!
Do not calculate percentage changes when the numbers are negative since they are extremely difficult to interpret. The change from +100 to -100 is -200% The change from -100 to +100 is also -200%. The percentage changes are the same but the underlying change is completely different.
You cannot. The starting value must be positive for a percentage change to make sense.
(B-A)/A * 100
devide 9 by 12
You do not. Percentage change (increase or decrease) makes sense only if both numbers are positive or both are negative. Consider the change from -50 to +50. You could calculate the percentage change as 100*(new-old)/old = -200% Now consider the percentage change from +50 to -50. -200% again! So, in percentage terms a change from +50 to -50 is the same as from -50 to +50.
Percentage change in QD = (QD2 - QD1) / QD1 For Example: QD1 = 100 QD2 = 120 then % change in QD = .2 or 20%
This is a problem that people face every day. If you spent 10% of your money on food last year and 20% of your money on food this year, how much did your spending on food increase as a percentage of your money? You solve this problem the same way you find any other change percentage: subtract the old value from the new value and divide that number by the old value. So, (20%-10%)/10% = 100%. The percentage of your money that you spend on food has increased 100% over last year.
Real GDP/Capita
The answer may depend on why the measurement is changing.
To calculate the money factor on a lease, you can convert the annual percentage rate (APR) to a decimal and divide it by 2400. This will give you the money factor, which is used to determine the finance charge on a lease.
They use percentage change because of the nature of the unit being described. The elasticity of demand specifies how much percentage demanded changes in response to a 1% increase in price.