Two-Column / ProofBlock Comparison

In the image below, we have a simple proof of triangle congruence, written in the two-column and ProofBlock formats. In comparing the two, notice how each of the statements in the two-column proof has become a connection between ProofBlocks. The rules governing the logical order of statements in traditional proofs are still evident in this format, with statements required to form a given conclusion being written before (to the left of) their conclusion.
The process of conversion to two-column proof is supported when students number statements from left to right, recognizing that the “reason” for each statement lies in the block that precedes it. In fact, even when moving their work into formats where connections are no longer visible, we have found that students still seem aware of the importance of theorems in justifying conclusions and what it means to logically order a proof.

To see an actual example of the conversion process, watch the video below: