Calculate percentage of a number, percentage differences, and value increases or decreases instantly.
Percentage of a quantity: Multiply the percentage by the value and divide by 100: (X ÷ 100) × Y.
Percentage change (Increase / Decrease): Subtract the old value from the new value, divide by the absolute value of the old value, and multiply by 100: ((New - Old) ÷ Old) × 100%.