Particles coagulation and fragmentation are ubiquitous (raindrop formation, air pollution, combustion, polymerisation, astrophysics) and mathematically described by the Smoluchowski coagulation and the fragmentation equations. Solving these equation accurately while preserving tractable computational costs is a tremendous numerical challenge, yet critical in astrophysics for understanding the formation of the planets. In particular, low-order numerical schemes do strongly overestimate the formation of large particles. We present a novel high-order discontinuous Galerkin algorithm (Lombart & Laibe, 2021) that addresses all these issues. This new algorithm paves the way to perform the first 3D simulations of dusty protoplanetary discs that include realistic coagulation/fragmentation.