This topic comes from Cheng Dawei's book The Family of Algorithms in the Ming Dynasty.

By grouping:

Every big monk eats three and every little monk eats one. We regard 1 big monk and three little monks as four people and 1 group, so 100 monks are divided into:

100÷4=25 groups

Because there are 1 big monks in each group, the number of big monks is: 1×25=25.

The number of young monks is: 100-25=75.

A: Yes. . . . . .