First of all, there is no white biscuit, which stands for 1, and the cardinality of each line is1;

The position of white biscuits, counted from the right, represents a few;

Then add up all the numbers represented by the white biscuits and add the cardinal number 1.

For example, in the fourth row, the white biscuits are 1 and 2 from the right, representing 1 and 2 respectively, 1+2+ 1 = 4.

In the sixth row, white biscuits are the second and third from the right, representing? Two plus three? 2+3+ 1=6

So the question mark should be 1+4+ 1=6.