1. The number of the last three disks is equal: 24/3=8 (pieces).

2. Take four pieces from the second set and put them into the third set, which means that the third set is 8-4=4 (pieces) and the second set is 8+4= 12 (pieces).

3. Take two pieces from the first set and put them into the second set, that is to say, the first set is 8+2= 10 (pieces) and the second set is 12-2= 10 (pieces).

To sum up; The first set 10, the second set 10 and the third set 4.