6+7-5=8 (only) the original on the second tree

25-8= 17 (original on the first tree only)

2、 12÷ 1/2=24

24÷( 1- 1/3)=36

36÷( 1- 1/4)=48

48÷( 1- 1/5)=60

60÷( 1- 1/6)=72

72÷( 1- 1/7)=84

Eat on the first day: 84× 1/7= 12 (only)

Eat the next day: 72× 1/6= 12 (only)

3. The least common multiple of one, two, three and four is 12, that is, 12 is a group, which just meets the conditions. A set of bowls is 12÷2=6 rice bowls, 12÷3=4 soup bowls, 65444.

12×5=60 (person)

Or equation solution: let the number of people be x, and get the equation according to the meaning of the question: x/2+x/3+x/4=65.

Solution: x=60

4. Assuming that two plates are added first, the topic becomes just two plates, and three plates are more than five. Analysis: The extra five sectors were originally 2×5= 10, and now this 10 is assigned to other sectors. Because each plate is divided into 1 person, it should be divided into 1× 10= 10 plates, so: one *. Plate 1 * * * has 10+5-2= 13 (only)

The area of a square is 6×6=36.

The area of the triangle is 36×4/9= 16.

The height AB of the triangle is: 16÷ 1/2 ÷6=5 and 1/3.