Rabbit (48-20x2)÷2=4.
Chicken 20-4= 16
4: 40 =(4 2/3)
3.7 liters = (3,700) ml.
The number of school chorus is between 50 and 60, and the ratio of male to female is 4: 7. There are (55) people in this choir.
Make this number proportional to 2, 0.8, 1/4. 2: 0.8 = 1/4: 1/ 10.