The surface area of the swimming pool to be tiled is 65 * 20+20 * 2 * 2+65 * 2 * 2 =1300+80+260 =1640m2 =1640 *10000m2.

The surface area of ceramic tile is 5*5=25 square centimeters.

So we need tiles1640 *10000/25 = 656000.

In fact, just calculate the surface area that always needs to be tiled.

The total area of ceramic tiles includes the bottom and edge of the pool.

Also pay attention to the conversion of units.