So this problem is almost complete. (I know you know that, just stating it.)
SO it appears that they have already determind that 5 12's could be divided into the hundreds place and 6 12's could be divided into the ten's place.
All we need to do is multiply 6 x 12 to find out what is missing from the box.
6 x 12 = ? Start with 6 times 2 - which is 12. Carry your ten. Multiply 6 times 10 and add the carried 10. The product is 72. When you place it in the box, you put the 7 under the 8 and the 2 under the 3 and THEN you need to add a zero to the end of your number making it 720.
If you were to continue the problem, you would subtract 720 from 839 and continue diving 12's into the remainder.
