How far is the distance between the post office and the cinema? This problem involves the distance calculation in mathematics. First of all, we need to know the initial distance between the post office and the cinema, and the relative position of the post office and the cinema.

Let's use a line segment to represent the distance between the post office and the cinema. Suppose the length of this line segment is d meters. The post office is on the left and the cinema is on the right.

The distance between the post office and the cinema is 100 meters. If the post office moves one meter to the right and the cinema moves one meter to the right, the distance between the post office and the cinema is d+a meters.

If the post office moves b meters to the right and the cinema moves b meters to the right, then the distance between the post office and the cinema is d+b meters.

If the post office moves c meters to the right and the cinema moves c meters to the right, then the distance between the post office and the cinema is d+c meters.

Therefore, we can draw a conclusion that the distance between the post office and the cinema is d+c meters.

It is known that the distance between the post office and the cinema is 1000m, the post office has moved 300m to the right, and the cinema has also moved 300m to the right, so the distance between the post office and the cinema is1000+300 =1300 m.

Therefore, we can draw a conclusion that the distance between the post office and the cinema is 1300m.