* The books span many years. The "Little House" series chronicles the Ingalls family's life from Laura's childhood in Wisconsin through their travels to Kansas, Minnesota, and finally, South Dakota.
* Laura's perspective. The books are told from Laura's point of view. We get a sense of the age difference between her and her sisters, but the exact ages aren't always stated precisely.
Here's a general idea of the age differences:
* Mary: Mary was the oldest sister. She was born in 1865, making her four years older than Laura.
* Carrie: Carrie was the youngest of the three Ingalls sisters. She was born in 1875, making her five years younger than Laura.
To get a more precise idea of their ages in each book, you'd need to refer to a specific book or chapter and look for details provided by Laura.
Would you like me to look up a specific book or chapter to try and find their ages?