Why do you think the germans take away the inmates' personal belongings and clothing? why do they cut off their hair? why do they tattoo a number on each person's arm?

The Germans removed personal belongings and clothings so that they could dehumanize them, and make them feel like they are nothing but property. They didn't want inmates to feel like individuals, which is why they shaved their heads - to remove every last part of their individualism.

They tattooed numbers onto peoples arms to accentuate that they were only property, just another number per say.