Solution

159962

First name
Grace
School
Meavy
Country
Age
8

The smallest number of answers you need to reveal for any given square grid is:

(nx2)-1

where n is the number of squares along one side.

The smallest number of answers you need to for any given rectangular grid is:

(a+b)-1

where a is the number of squares along one side and b is the number of squares along the other side.