Mathematics is about finding better ways of reasoning. But for many applied mathematicians, the primary mission is to shape their minds in a way that gets them closer to the truth. The calculations are secondary, the real question is: how we can better understand the world around us? In this Oxford Mathematics Public Lecture, David takes us on a journey through applied mathematics from statistics all the way to complexity theory, lifting examples from his work with football clubs - signing the best players (statistical thinking) or organising an attack (complex thinking) - and from every day life - bickering less with our partners (interactive thinking) and learning to let go (chaotic thinking). David reimagines applied mathematics as a set of tools for life, from big work decisions to how we treat our friends, family and work colleagues. No problem is too big or too small for a mathematical solution. Professor David Sumpter is author of five books including Soccermatics (2016), Outnumbered (2018) and Four Ways of Thinking (2023). His research covers everything from the inner workings of fish schools and ant colonies, through social psychology and segregation in society, to machine learning and artificial intelligence.