Dyscalculia, also known as developmental dyscalculia, is a learning disability characterized by significant difficulties with numerical and arithmetic skills. Early signs can include trouble determining the number of objects in a small group without counting. Other common symptoms involve challenges with memorizing math facts, organizing numbers, and distinguishing between different representations of numbers, such as the numeral '3', the word 'three', and various mathematical symbols. Research also suggests an association between dyscalculia and specific changes in brain activity and structure.