I called my mom's parents Grandma and Grandpa. I called my dad's parents Grandma and Grandpa with there last name attached.

My daughter Calls my mom: Grandma, my dad and step mom: Grandpa/Papa and Grandma. She calles my husbands parents Nana and Papa.

Personally I would prefer that she called them all just Grandpa and Grandma with thier first names attached. But I didn't get any say in the Nana and Papa thing.