Calculate percentages for discounts and tips.
Percentage = (part / whole) × 100%; percent change = (new − old) / old × 100%.
A $40 item on 25% sale saves $10, for a final price of $30.
Multiply the number by the percentage as a decimal. For example, 20% of 50 is 50 × 0.20 = 10.
Divide the difference by the original amount and multiply by 100 to get the increase or decrease as a percentage.
Yes. Use the percentage of an amount to compute tips, discounts, and tax.