# 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