Unlike untimed Petri nets, representation of the state of a timed Petri net and describing its evolution is not an easy task. Here, an approach, called place-stretching, is introduced to represent the state of a timed-place Petri net. This approach also facilitates the description of the evolution of the state of a timed-place Petri net. An algorithm, which uses this approach, to construct the reachability set of a timed-place Petri net is also developed. An example is also presented to demonstrate the introduced approach and the usage of the developed algorithm.