In the top squares of the slips the ten digits are written, and each slip contains in its nine squares the first nine multiples of the digit which appears in the top square.
With the exception of the top squares, every square is divided into two parts by a diagonal, the units being written on one side and the tens on the other, so that when a multiple consists of two figures they are separated by the diagonal.
I shows the slips corresponding to the numbers 2, o, 8, 5 placed side by side in contact with one another, and next to them is placed another slip containing, in squares without diagonals, the first nine digits.
It has the usual rectangular plan, with several pretty squares and straight, clean, well-paved streets.
This method of numeration dates from the time of Guzman Blanco, but the common people adhere to the names bestowed upon the city squares in earlier times.