A great video showing the master tactics of Alexander the king of Macedon and his generals, crushing the Persian forces. Note that the sources for the army could vary, but here are the most accurate:

13,000 peltasts,[1]
22,000 heavy infantry,[2]
5,850 cavalry[2]
Total: 40,850
60,000–80,000 Persian infantry [3]
11,000 cavalry[2]
10,000 Persian Immortals
10,000 Greek mercenaries[4]

Total: 50,000–108,000 (modern sources)
250,000–600,000 (ancient sources)