I read in the book Tarot for yourself: A workbook for personal transformation by Mary K. Greer that the major arcana can be represented in numerology.  By adding the numbers of your birthday "MM/DD/YYYY" M+M+D+D+Y+Y+Y+Y = Personality card and soul card.

Personality card indicates what you have come into this life to learn.
Soul card shows your soul purpose through all your life times.  

My soul card came out to be 22 and she attached that card to THE FOOL
My personality card came out to be 4 THE EMPEROR  

So in that case what would THE FOOL signify as being a soul card?

She said "THE FOOL - the number of great impulsiveness and great mystery a fine line to balance."

Hi LS
The Fool is a "Joker" Card. It can be placed anywhere, in placing it at the end, let me take some excerpts:

Placing the Fool in position 22 – Tav, Cross, is significant if seen from a perspective of the Deity (Christ and Odin) offering the highest sacrifice for the righteousness of the masses, and spiritual enlightenment. We continue our thought and include Osiris, The Egyptian Sun God. His sublime symbol is X. Today we associate X with ten, which describes attainment. The symbol X has also become the symbol of “Resurrection and Rebirth”; this symbol can be seen, especially among the Freemason, Rosicrucian and Illuminati societies.

We all know that our soul do not die when the spirit is withdrawn by God. The body dies, to be returned from where it originated. Our immortal soul has a road to walk beyond the mere Cosmic, before being reincarnated in another human being. Another life, with its own goals to be met. This is a necessary cycle for the soul to achieve purity and attainment.

Although the Fool is an unnumbered card, I assign him to Tav-22. The next step Kaf/Kaph-23 is then “The Throne”. In being the first additional card, it is also the most logical step beyond death. We will stand before our God to be assessed.

The Fool’s dreams and objectives can stretch beyond the limitations of humanity and can include the quest to ascend higher than God. Becoming God or even higher, the folly in these thoughts and ambitions can only be directed and negated by the Creator. The obvious result is seen in the Moon card whereby even mental illness can be foreseen. However should the Fool gain enough wisdom, seek guidance from God, and consider his limitations, his success is depicted on the Sun card.

Blessed be