Opposite faces of a cube

In your book, Maths Mela (Chapter 1), you look at a die. A die is a cube with the numbers 1 to 6 on its faces. The face with 6 is opposite the face with 1: when 1 is on top, 6 is at the bottom. The faces 2, 3, 4 and 5 go round the sides. Each of them shares an edge with the face 1. Only 6 has no edge in common with 1.

Every face of a cube has 4 neighbours, which share an edge with it, and 1 opposite face, which it never touches. A cube has 6 faces, so it has 3 pairs of opposite faces.

The book shows three views of one coloured cube. In each view you can see three faces: the front, the top and the right side. View 1: red front, orange top, green right. View 2: orange front, purple top, green right. View 3: blue front, red top, yellow right. Faces seen together in one view all meet at a corner, so they are neighbours, never opposite.

What is opposite red? Red is seen beside orange and green (view 1) and beside blue and yellow (view 3). That is 4 neighbours. The only colour never seen beside red is purple, so purple is opposite red. If we could hold the cube as in view 1 and see all six faces, we would find: red front and purple back, orange top and yellow bottom, green right and blue left. So orange is opposite yellow, and green is opposite blue.