And now for a little humour.
This is from a book by one of the most famous fly fishermen of all time. You don’t have to know anything about fishing; just pay attention to the math.
“…to know what…size tippet to use, divide the size of the hook by three…”
In case that is not clear, he clarifies the rule with an example.
“…For example, if you are using a size 12 dry fly, divide by three, and use a 4X tippet…”
But wait; then there is this.
“…A similar rule that arrives at pretty much the same place is that you should multiply the tippet size by three to determine the correct hook size…Thus, if you were using a 4X tippet, three times that would dictate the use of a size 12 hook…” (The italics are mine.)