Profit and loss problem's formula (1) has a surplus once and a deficit once. The formula can be used: (surplus+deficit) ÷ (the difference between two distributions per person) = number of people. (2) There are two surpluses (surpluses), and the formula can be used as follows: (large surplus-small surplus) ÷ (the difference between two distributions per person) = number of people. (3) If twice is not enough (loss), the formula can be used: (big loss-small loss) ÷ (the difference between two distributions per person) = number of people. (4) One time was not enough (deficit), and the other time was just finished. The formula can be used: deficit ÷ (the difference between two distributions per person) = number of people. (5) One time there is surplus, and the other time it is just used up. The formula can be used: surplus ÷ (the difference between two distributions per person) = number of people.