Question

why did grandmother want to read and write

Answer 1

Reason may be loneliness or may be her interest in reading or writing and some people wants to be aware of everything thing so they read

Answer 2

Grandmother was fond of the kashi yatre and wanted to know the episodes. When her granddaughter left her for few days she felt very upset and was eager to know the story.

She thought that if she could read and write she will become independent so she was determined to learn kannada language.

Hope it helps!