elf + elf = fool

What counting number (whole number, positie) do each of the letters stand for?

Hint: It may help to write the problem vertically.

Suppose the following statements are true.  It takes a minimum of four United States coins to buy an apple.  To buy two applies, you need a minimum of six coins.  To buy three apples, you need no more than two coins.  How much does the apple cost?

Susan Teacher, John Writer, and Mary Potter work as a teacher, a writer, and a potter.  No one, however, works at the occupation that corresponds to his or her last name.  Each person has a child with the same last name that assists one of the other two.  No child works at the occupation that corresponds to his or her last name.  If John Writer is not a potter, what does Susan Teacher’s child do?

Three boxes are in a room. You know that one contains apples, one contains oranges, and one contains a mixture of apples and oranges, but you don’t know the contents of the specific boxes. The boxes are labeled “apples,” “oranges,” and “apples and oranges,” but each box has the wrong label on it. You must identify the contents of each box by picking only one piece of fruit from only one box. You are not allowed to feel the fruit! How can you identify the contents of each box?