The main purpose of this paper is to provide an overview of some discrete inequalities for real and complex numbers. These include: inequalities between elementary means, the Cauchy inequality as well as some refinements and generalisations of Cauchy inequality. Furthermore, the paper encompasses the Abel inequality, Čebyšev’s inequality,the Grüss inequality and the Biernacki inequality. Lastly, it brings brief survey of inequalities for convex functions such as Jensen’s inequality and the Petrović inequality.