Box method

The box method is a multiplication algorithm which is taught in some British schools as an alternative to the traditional method of long multiplication. It a simplified version of the lattice method. It can also be used to aid mental arithmetic.

The method

The above diagram shows the example of 345 x 12.

The problem is split into six very simple multiplications:

10 x 300 = 3000

2 x 300 = 600

10 x 40 = 400

2 x 40 = 80

10 x 5 = 50

2 x 5 = 10

So the problem is simplified to the following addition:

3000
 600
 400
  80
  50
  10
----
4140