What is the "pinch index"?

In the past, fortune tellers used to count the five elements by hand, and figuratively speaking, they just pinched their fingers with their thumbs (in fact, they clicked, and the fortune teller's nails were very long, as if they were "pinched").

The thumb is gold, followed by wood, water, fire and earth.

And a, b, p, d, e, h, n, n "ten days' work"

Zi Chou Mao Yinchen applied for "Twelve Branches" at noon.

Sometimes I do mental arithmetic, but I can't bring tools and abacus. I don't have much body, so I rely on my hands ~ ~ ~