Draw a rectangle, divide it into cells with corresponding digits multiplied by digits according to the digits of two multipliers, write down the digits of multiplier and multiplicand in turn at the edge of the cell, then divide the cell into two by diagonal, record the ten digits and single digits of the product corresponding to the above digits respectively, add these products from right to left along the diagonal, and move forward when they reach ten.

For example, to calculate the product of 128 multiplied by 456, first draw a rectangle and divide it into 3 times 3 cells, then write down the digits of the multiplier and the multiplicand in turn at the edge of the cell, then divide the cell into two by diagonal, record the ten digits and the single digits of the product corresponding to the above digits respectively, add these products from right to left along the diagonal, and when they add up to ten, move forward to get 65438.

Introduction:

Lattice multiplication is often used in multiplication formulas with two or more bits. Compared with the commonly used column vertical algorithm, lattice multiplication takes a little longer, but the correct rate is much higher than that of the column vertical algorithm.

Lattice algorithm is between drawing lines and calculating formulas. After this method was introduced into China, it was called "Pavilion" by Cheng Dawei, a mathematician in the Ming Dynasty, in his book Arithmetic Unity.