Math problem: Xiaohua bought 34 commemorative stamps from 2 yuan and 5 yuan and used them in 98 yuan. How many stamps did he buy each? By the way, the formula of chicken and rabbit in the same cage.

Solution:

Suppose I bought X commemorative stamps from 2 yuan and Y commemorative stamps from 5 yuan.

So 2x+5y=98.

x+y=34

X=24，y=， 10。

Chicken rabbit cage formula

Solution 1: (rabbit foot number × total foot number-total foot number) ÷ (rabbit foot number-chicken foot number)

= Number of chickens

Total number-number of chickens = number of rabbits

Solution 2: (total number of feet-chicken feet × total number of feet) ÷ (rabbit feet-chicken feet)

= the number of rabbits

Total-number of rabbits = number of chickens

Solution 3: total number of feet ÷2- total number of heads = number of rabbits.

Total number of rabbits = number of chickens.