Here you see the front and back views of a dodecahedron which is a solid made up of pentagonal faces. Using 20 of the numbers from 1 to 25, each vertex has been numbered so that the numbers around each pentagonal face add up to 65. The number F is the number of faces of the solid. Can you find all the missing numbers? You might like to make a dodecahedron and write the numbers at the vertices.