Formula : 1 Mark
Each missing number : 1 Mark each
From Euler’s formula we know that
F + V - E = 2
In first column,
F+6−12=2⇒F=8
In second column,
5+V−9=2,⇒V=6
In third column,
20+12−?=2,⇒E=30
Faces8520Vertices6612Edges12930