The method then consisted of four steps:
1. Use elementary row and column operations to remove
all zeros from the interior of A.
2. Find the 2 × 2 determinant for every four adjacent terms
to form a new (n–1) × (n–1) matrix B.
3. Repeat this step to produce an (n–2) × (n–2) matrix, and
then divide each term by the corresponding entry in the interior
of the original matrix A, to obtain matrix C.
4. Continue “condensing” the matrix down, until a single
number is obtained. This final number will be det A.
As an illustration of Dodgson’s method, let’s consider the 5× 5
matrix