Mathematics appears to be both discovered and invented. While mathematical concepts like shapes, sizes and quantities have always existed in nature and been waiting to be discovered, many mathematical tools, systems and theories have been invented by humans over centuries to help develop mathematics as a formal science. Key inventions include numerical systems, abstraction of concepts, and tools like the abacus, while mathematical objects and patterns in nature have been discovered through observation and study. Overall, mathematics has advanced through both the discovery of principles present in the universe and the invention of tools and ideas to formally express and apply these principles.