To Find The Difference Between Two Numbers The Greatest Of Which Is
unknown.
Take as many nines as there are figures in the smallest number, and
subtract that sum from the number of nines. Let another person add
that difference to the largest number, and, taking away the first
figure of the amount, add it to the last figure, and that sum will be
the difference of the two numbers.
For example: Robert, who is 22, tells George, who is older, that he
difference of their ages. Thus, the difference between