Abstract: Timing refers to duration discrimination, and counting refers to number discrimination. There are some similarities that they have same principles, and that the memory of time and number are affected by time dalay, and that cross-modal and drugs play consistent roles. Based on Mode-control model, timing and counting share common mechanism. The viewpoint of Magnitude theory is that time and number possess the partial overlapping mental representation. The brain areas are involved prefrontal, parietal, cerebellum and basic ganglia. Many evidences have indicated timing and counting have some same properties as well as divergences. However the possibility whether there is shared common magnitude representation or their mutual action occurs response selection stages needs to be researched further.

Key words: timing, counting, Mode-control model, A Theory Of Magnitude, intraparietal sulcus, posterior parietal cortex