Pinch your fingers for fortune-telling time _ fortune-telling pinch your fingers

How do blind people calculate a perpetual calendar? What is the formula?

The perpetual calendar turns once every 60 years. Fortune-tellers can calculate any year by remembering one point.

As for the blind, they often index by hand, because mental arithmetic is always not so easy. Use different joints on the hand to represent different heavenly stems and earthly branches. You can count it easily.