What are the rules Rivka follows to stay alive one day at a time in The Devil's Arithmetic?
Unlike the others, Hannah knows what is going to happen because she is from the future. She has to learn to survive along with them. Some of the others are skeptical of Rivka’s authority, but Hannah accepts it.
You must listen if you wish to stay alive. I know the things you need to know in this place. There is the malach ha-mavis, the Angel of Death, hovering overhead. But we can fool him if we follow the rules. (p. 113)
Rivka explains that they can call each other by their names, but they must learn people’s numbers. For instance, you never stand next to a person with a G, because the G stands for Greek. Since the Greeks don’t understand directions, they don’t survive long. Standing next to them, you can become collateral damage.
While you should avoid people with G in their number, you should stay close to people with lower numbers. A lower number means you have been in the camp a long time, and know how to survive.
Hannah describes the rules as “craziness,” but they make sense. The more you know, the more likely you are to survive.