Cori is 3 years old today.  In 5 years, she will be one-third the age of her aunt.  How old is her aunt today?
In 5 years, Cori will be 3 + 5 = <T>add(3, 5)=8 years old.
In 5 years, Cori’s aunt will be 8 x 3 = <T>multiply(8, 3)=24 years old.
Today, her aunt is 24 - 5 = <T>subtract(24, 5)=19 years old.
