This explanation is more troublesome. Take the numbers in the title directly as an example. A 1/4 circle starting from the upper left corner of the circle, that is, 3,

The innermost circle is 3, the second circle is 1 and 5, 1+5=6, which is twice as much as 3.

The third circle is 9 and 3, 9+3= 12, which is four times that of 3.

The fourth circle is 12 and 12, which add up to 24, 8 times that of 3.

See, every part has such a multiple relationship, so the answer in the question mark should be the lower left corner, any circle can be used, for example, the outermost circle, 12 and 24 are added to get 36, and 8 is divided by 4.5.

Of course, you can also divide the simplest inner rings 6 and 3 by 2, as I said at the beginning.

The answer is (6+3)÷2=4.5.