1. On the first day, * * * takes out A times A, which is the cube of A.

2. The next day, * * * took out B times B, which is B's cube sugar.

3. On the third day, * * * took out the cube of (A+B) multiplied by (A+B), which is (A+B).

4. On the third day, the amount of sugar is more or the same. Because A+B must be greater than or equal to a or b, the larger the square number, the greater the result; But when A=B=0, there is the same amount of sugar in three days.