The prealgebra curriculum presents many opportunities for encouraging students to justify their inferences. Requiring students to communicate clearly the reasoning behind their solutions, with appropriate mathematical language and notation, helps lay the groundwork for future, proof-based mathematics courses. Prealgebra students can even be introduced to formal proof in several contexts. Once they have a basic concept of what it means to "prove" something, conversations naturally arise about what steps must be included in a rigorous proof and the difference between conjecture and proof. This article presents classroom activities and discussions that are rich with opportunities for motivating prealgebra students to engage in proof and for spurring conversations that lead to greater proof readiness in students before a formal, proof-based geometry course. (Contains 8 figures.)