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Here you see the front and back views of a dodecahedron which is a solid made up of pentagonal faces.
Using twenty 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.