Take the UK as an example, the pre-tax price is 10 pounds, the tax rate is 20%, and the actual sales price is 12 pounds. The profit is calculated based on 10 pounds, that is, sales price = actual price before tax * (1 + 20%), 20% is the tax rate. The same is true for other countries. The simple calculation method is, actual price = sales price (the price you see) * 5/6 = sales price * 0.83.