Which little house book is Frederick ingalls in?

Frederick Ingalls is not a character in the Little House books.

The Ingalls family in the Little House series consists of:

* Charles Ingalls: The father

* Caroline Ingalls: The mother

* Mary Ingalls: The eldest daughter

* Laura Ingalls Wilder: The second daughter

* Carrie Ingalls: The youngest daughter

* Grace Ingalls: The youngest daughter (adopted)

Perhaps you are thinking of a different character or book? Could you provide more context or information?