Surplus, surplus; Loss, loss of several people to distribute some goods, and then according to the distribution of two kinds of profits and losses to determine the number of people and goods.

Formula: number of people = profit-loss difference ÷ distribution difference (big difference ÷ small difference)

Compared with the hypothetical method, the difference between profit and loss is not necessarily the difference between two profit and loss numbers, but the difference between two gains and two losses, and the sum between one profit and one loss (the actual difference greater than 3 and less than 2 is 5).

Second, examples

1. Give the children a bag of candy. If you give two each, there will be more 10, and if you give three each, there will be five less. Find the number of children and the total number of sweets.

Analysis: One profit and one loss, the difference between each person is 3-2 = 1, and the total difference is 10+5 = 15.

Number of people: (10+5) ÷ (3-2) = 15 (person)

Number of sweets: 15× 2+ 10 = 40 (person)

Students go to plant trees. If everyone plants 6 trees, there will be less 13 seedlings. If everyone plants five trees, it's over. Q: How many students are there? How many seedlings are there?

Analysis: Everyone's difference is 1, and the total difference is 13.

Student: 13 ÷ (6-5) = 13 (name)

Seedling: 13× 5 = 65 (plant)