(40-12) * (30-12) * 6 = 3024 cubic centimeters.

Other questions:

1. One fifth = two tenths, and one quarter = two eighths, so the answer can be two nineties.

One fifth = three fifths, one quarter = three twelfth. . . Thirty-three, thirty-four, whatever.

2. The first addend minus 0 will be minus 10 times, which means that the first addend is minus 10 times of the second addend. So 682 is divided by 1 1=62.

These two numbers are 62 and 620 respectively. You can also do equations.

3. 1989 divided by 19= 102 and 5 1. . 5 1 is the 20th number in the middle. Maximum odd number =5 1+ 19*2=89.