What does Rivka share with the girls about the rest of her family in "Devil's Arithmetic"?
Rivka tells the girls that she has been at the camp for a year. In that time, her mother and her sisters, her father, and her brother have all been exterminated. She relates that her mother had been killed because she had been "coughing too badly to work", and that her three younger sisters had been incinerated as well because "they would not leave her side". Rivka's father and her brother Saul were eliminated because "they were too angry, too strong, too outspoken". Rivka and her brother Wolfe are the only ones in their family remaining. Rivka, pragmatic and hardy, works to guide those who are new to this place of horrors on how they too might survive, and she helps whomever she can by "organizing", or surreptitiously securing, much needed supplies and items for living. Rivka's brother, Wolfe, however, is a Sonderkommando, one of the "walking dead" who transport bodies to and from the ovens. His ghoulish assignment has so undermined his spirit that she says, "He might as well be with them", the dead members of his family (Chapter 14).