This article describes the outcomes of using a scaffolded set of two digital, simulation-based approaches to support secondary mathematics and science preservice teachers (PSTs) in learning to facilitate argumentation-focused discussions. The researchers investigated PST and teacher educator (TE) impressions of the experience and collected evidence of change in PSTs' understanding of argumentation, beliefs, and skills in facilitating argumentation-focused discussions, working within mathematics and science methods across six institutions. PSTs and TEs endorsed future use of the approach. Pre/post improvement in beliefs was evident across quantitative and qualitative data sources. There was less clear evidence of improvement in understanding of argumentation, although understandings at both time points were aligned with the study's vision. Evidence of improvement in skill was mixed with quantitative results showing no improvement and qualitative results showing evidence that PSTs and TEs believed PSTs' skills had improved.