Meg has 5 milligrams of zinc and 0.93 milligram of silver.
how much more zinc does she have than silver?

-- Start a list.
-- At the beginning of the list, write zero. 
-- Next on the list, write ' 1 '.
-- Now you have the beginning of the Fibonacci series.
-- Whenever you want to add a new term to the list, sum up
     the last two terms on the list.  Their sum is the new term.