I want to know what an iron abacus is, how to use it and how to predict it. This is a book of prophecy.

Explanation: The metaphor of careful calculation, the metaphor of a person who is good at calculation, is also a kind of fortune telling.

Source: Qing Wu Ren Jian's "The Present Situation of Wonders Witnessed in Twenty Years" 3 1: I asked: "What is that iron abacus?" Zi An said, "This is a fortune-telling name. Probably fortune tellers are arranged in eight characters, and the words that come out are written according to his will. Only this iron abacus is engraved on the book. Arrange eight characters instead of five lines, only talk about numbers, stack the figures of eight characters and look them up in the book. I don't know how he added, added and looked them up. Every time he checks, there is only one word, which is added slowly and written naturally. The judgment is very effective. " I said, "If anyone knows this at the moment, why not do the math?"