1. Looking at the arrangement rules horizontally: each line goes from left to right, which line is it currently in? It starts from the number 1 to the current line number, multiplied by the current line number respectively, and increases from left to right.

2. Looking at the arrangement law vertically: from top to bottom of each column, in which row is it currently, the current column number is multiplied by the current column number respectively, and the numbers increase from top to bottom in turn.

3. Look sideways at the arrangement rules: the outermost hypotenuse is the current number of rows multiplied by the current number of columns, and the two numbers are the same, increasing from top to bottom.

The multiplication formula is the basic calculation rule of multiplication, division and square root in ancient China.