This chapter looks at letters-to-numbers problems, an interesting class of problems that entail many insightful strategies. Letters-to-numbers problems strongly fulfill the four conditions of demonstrability of Laughlin and Ellis (1986) and are thus highly intellective. Condition 1 is that the group members must agree on a conceptual system. Condition 2 is that there must be sufficient information. Condition 3 is that the member(s) who do not know the correct answer should be able to recognize it if it is proposed by another group member. Condition 4 is that the member(s) who do know the correct answer have sufficient ability, motivation, and time to demonstrate it to the incorrect member(s).