This essay proposes a reflection on the learning difficulties and teaching approaches associated with word problem solving. We question the development of word problem solving skills in the early grades of elementary school. We are trying to revive the discussion for two reasons. First, the knowledge in question—reversibility of arithmetic operations and flexibility of mathematical thinking—is the key element in elementary mathematics. Second, we hope to create a shift in the understanding of this knowledge development in students. Using the folk tale “The Three Little Pigs” as a metaphor, we analyze difficulties students experience while learning to solve word problems involving addition and subtraction. We formulate a hypothesis about the cognitive duality of word problem solving. This hypothesis explains a number of well-known learning difficulties and suggests teaching principles that could help avoid developmental obstacles and pitfalls within the teaching/learning process.