What advice does Rivka give the girls to help them survive camp?

Rivka tells the girls they will have to be smart, pay attention, and know when to avoid a prisoner who may end up getting them killed.

She tells them to learn to read the number and be able to decipher between the good and the bad. She tells them that a number with a "G" means the Jew is Greek and cannot communicate... that the Greek Jews do not last long in the camp. She also notes that those with lower numbers, like herself, have been in the camp the longest.... that they can give the best advice because they are survivors.