How do you tell numbers from letters in braille?

In Braille, numbers are represented by the same configurations as the first ten letters of the alphabet (A-J), but they are preceded by a number sign, which is a specific combination of dots (dots 3, 4, 5, and 6). This number sign indicates that the following characters are to be interpreted as digits rather than letters. For example, the Braille cells for the letters A through J correspond to the numbers 1 through 0, respectively. Once the number sign is used, readers can distinguish between letters and numbers based on this context.