This book is a collection of the works that have been conducted by researchers at various universities in the world. The emergence of disruptive technologies has led to a significant change in the role of mathematics and statistics for problem solving, with the use of sophisticated software and hardware in solving complex systems and process. In the era of digital technology, mathematics and statistics need to be highly relevant to be able to cater for the needs of Industrial Revolution 4.0 (IR 4.0) such as big data analytics, simulation, autonomous system and cloud computing. Motivated by this development, a total of 26 chapters are contributed by respectable experts that actively involve in many researches and grants. The main scope of the book is to conduct a new system of modelling and simulations on solving differential equations, nonlinear equations, energy, epidemiology and risk assessment. This book will be of interest for postgraduate students, researchers as well as other scientists who are working in numerical modelling and simulations based on efficient mathematical and statistical techniques.