Place-value structure of the Arabic number notation is akey why math is difficult for a subgroup of people with dyscalculia Abstract: Developmental dyscalculia (DD) is a math-specific learning difficulty that is believed to be a multi-cause condition. Former measurements found that typically developing adults and children process place-value number notations (such as the Arabic numbers) harder than sign-value notations (such as the Roman numbers) in simple mathematical tasks. Computational considerations suggest that place-value notation processing requires more intensive use of executive functions compared to sign-value processing. Other works have demonstrated that executive function may be impaired in DD. Based on these details, it is possible that place-value notation handling is also impaired in DD. Here, we contrasted the performance of a DD group and a typically developing control group in an artificial sign-value and place-value number notation comparison task. It was found that place-value notation handling is impaired in a subset of participants living with DD. We argue that a possible domain-general executive function deficit may lead to domain-specific mathematical problem-solving difficulties, with the mediation of a fundamental component of the mathematical tasks, here, with the decoding of the unintuitive place-value number notation system. Based on these results, it is possible to design new types of training materials and aiding tools that can help persons living with dyscalculia to understand and handle multi-power numbers more efficiently.