Numbers
The number 5 in braille
5 is the number sign followed by the letter e — dots 1 and 5.
Number sign + e
Dots 3-4-5-6, then dots 1-5
Why it uses a letter
The first ten letters of the alphabet double as the ten digits. e is letter 5 of the alphabet, so after a number sign it reads as 5. Without the number sign the same cell is simply the letter e — see E in braille.
5 inside larger numbers
A number sign covers the whole run of digits that follows it, so these examples each use one indicator regardless of length.
5
15
500