Assuming a $1-$KB page size, for the address reference $650000$

a$.$

The page number $=3,$ and the offset $=13$

b$.$

The page number $=634,$ and the offset $=784$

c$.$

The page number $=634,$ and the offset $=111$

d$.$

The page number $=210,$ and the offset $=161$