1)My sister is six years older than my elder brother.
My brother is six years younger than my sister.
2)My mother is three years younger than my father.
My father is three years older than my mother.
3)My father's mother is twenty five years older than my father.
My father is twenty five years younger than my father' s mother.
4)My uncle is half a year older than his wife.
His wife is half a year younger than my uncle.