5. Recently, the Asian football tournament has sparked Wang Xin, a junior high school student, to research football. He found that the football is made by gluing black and white leather pieces together, with black pieces being regular pentagons and white pieces being regular hexagons (as shown in the figure), and he counted 12 black pieces. Then, the number of white pieces is $\qquad$ pieces.
5.20.

Let there be $x$ white blocks, then the white blocks have a total of $6x$ edges, and the black blocks have a total of 60 edges. Since each white block has 3 edges connected to black blocks and 3 edges connected to other white blocks, then $6x \div 2 = 60, \therefore x = 20$.