MATH PUZZLE: Can you replace...

At Sunday School they were teaching how God created everything, including human beings.

Little Johnny, a child in the kindergarten class, seemed especially intent when they told him how Eve was created out of one of Adam's ribs.

Later in the week his mother noticed him lying as though he were ill, and said. "Johnny what is the matter?" Little Johnny responded, "I have a pain in my side. I think I'm going to have a wife."