Mama's comment emphasizes the importance of teaching Walter Lee to understand and make good choices.
The intent of Mama's comment, "You make him understand what you doing. Walter Lee You teach him good," is to express her belief in the importance of teaching Walter Lee, her son, how to navigate the world and make wise decisions. She wants him to be responsible and knowledgeable in his actions and choices.
By saying "You teach him good," Mama is emphasizing the need for Walter Lee to instill positive values and morals in himself and others.
The probable question may be:
Why does Mama emphasize the importance of teaching Walter Lee to understand and make good choices in 'A Raisin in the Sun'?