To calculate the grid, first look at how many grids are at the bottom, and then look at the hidden grid. Calculate the hidden grid from the front and side, and add them together.

Mathematical competition is one of the effective means to discover mathematical talents. Mathematics competition in the modern sense began in Hungary.

Mathematics competition is similar to sports competition. It is an intelligence competition for teenagers, so the Soviet Union pioneered the term "Mathematical Olympics". In similar intelligence contests with basic science as the competition content, mathematics competitions have a long history, with many participating countries and the greatest influence.