Question on the balance of open orders

Hello, can someone tell me how to calculate the average balance of the price of open orders. For example: 1 lot bought for 10 rubles, 1 lot
sold for 100 rubles, in this case, at a price of 45 rubles, both orders will have an equivalent income. And how to calculate the average price if you bought 1 lot at
10 rubles, and sold 2 lots for 80 rubles and 1 lot sold for 100 rubles?