Dyscalculia is a learning disorder that makes it hard to understand numbers and calculations. People who really struggle with math are sometimes diagnosed with dyscalculia.
Dyscalculia, literally "counting badly," comes from the Greek dys-, "badly," and the Latin calculare, which means "to count." People with dyscalculia have brains that work perfectly well in other areas, like reading or spatial reasoning. But when it comes to numbers, they have enormous difficulty. Often, a young child with dyscalculia can't look at several objects and calculate how many there are — it's an early sign they might have the condition.