How to create fun in Math#How to learn Math with fun.

There are 4 rows each containing 15 coins. If we add one coin to each row the total number of coins should increase. However, by just rearranging (moving) the coins. We can still have only 15 coins in each row, just like in the beginning. So what happens the 4 extra coins we added? The trick is that we are counting the corner coins twice. If we place one coin at the intersection the number of coins per row not increases when moving coin to side row. Try moving the coins practically and see the magic --- Enjoy the fun Math.