Math Puzzle 2. [solution]

Original piles:

First move:

You move 7 pieces from the pile containing 11 pieces (left side) and add them to the 7 (middle pile ).

Second move:

You move 6 pieces from the pile that contains 14 pieces right now (middle pile) to the 6 (on the right).

Third move:

Move 4 cubes from the pile that contains 12 pieces right now (on the right side) to the 4 (on the left side).

You are done ! Each pile now contains 8 pieces after 3 moves.