Foundation and Year 1/2 teachers at Saint Martin de Porres Primary School, a Catholic School in Laverton, Melbourne have been collaborating with a team of researchers from Monash University on a four-year project led by Professor Peter Sullivan and colleagues. The teachers have been trialling and implementing a series of lesson sequences as part of an Australian Research Council grant. The project focused on Exploring Mathematical Sequences of Connected, Cumulative and Challenging Tasks (EMC[superscript 3]) (Sullivan et al., 2023). Throughout the project, Dr. Sharyn Livy made regular school visits to work with the teachers and assisted them when implementing the approaches and lesson structure for teaching with challenging tasks (Sullivan et al., 2020a; Sullivan et al., 2020b). To support teaching and student learning the Foundation and Year 1/2 teachers met fortnightly to plan for mathematics. With the guidance of Sharyn and the mathematics leader Elise, the teachers extended their approaches for planning lessons when teaching with challenging tasks. This article shares planning and assessment practices that have evolved over several years to effectively support the implementation of sequences of challenging tasks at this school.