Percentages

Converting

Converting percentages to fractions - the number over 100
Converting percentages to decimals - divide by 100
Converting decimals to percentages - multiply by 100

Quick Percentages

Percentage	Decimal	Fraction
1%	0.01	1/100
2%	0.02	2/100
3%	0.03	3/100
5%	0.05	5/100
10%	0.1	10/100
20%	0.2	20/100
50%	0.5	50/100
75%	0.75	75/100
90%	0.9	90/100
100%	1.0	100/100

Calculating Percentage Increase

A = Amount Afterwards	B = Amount Before	P = Percentage Change
A = B * (1 + P)	B = A / (1 + P)	P = (A - B) / B
salary is B increased by P%	salary is increased by P% to A	salary was B is now A (A > B)
P% more than B		B increased to A
B plus P%

Calculating Percentage Decrease

A = Amount Afterwards	B = Amount Before	P = Percentage Change
A = B * (1 - P)	B = A / (1 - P)	P = (B - A) / B
salary is B decreased by P%	salary is decreased by P% to A	salary was B is now A (B > A)
P% less than B		B decreased to A
B minus P%

Compound Percentages - Increase

This is when there are two percentage increases

Compound Percentages - Decrease

This is when there are two percentage decreases