1. Schwarz methods by domain truncation Martin J. Gander and Hui Zhang; 2. Turnpike in optimal control of PDEs, ResNets, and beyond Borjan Geshkovski and Enrique Zuazua; 3. Reduced basis methods for time-dependent problems Jan S. Hesthaven, Cecilia Pagliantini and Gianluigi Rozza; 4. Mixed precision algorithms in numerical linear algebra Nicholas J. Higham and Theo Mary; 5. Asymptotic-preserving schemes for multiscale problems Shi Jin.