13 x 7 is 28 Abbot and Costelo Funny Proven Video

This is very funny video of old comedy artists Abbot and Costelo. One is boss and other one is employee. Employee try to proven 13 X 7 is 28. What do you say can you proven it? We all know 4 x 7 = 28. But somehow employee proven it to his boss 3 times and finally he got fired.