Mulank
Your mulank — the radical or birth number — is the day of the month you were born on, reduced to a single digit. Someone born on the 23rd has mulank 5, because 2 + 3 = 5. It is the most immediate of the three numbers: it describes how you meet the day, how you come across in the first hour of knowing you, and it is the only one that changes if you were born a day earlier.
Bhagyank (Life Path)
Your bhagyank — the destiny number, and the same figure Western numerology calls the Life Path — is your whole birth date reduced to a single digit: day, month and year added together. Where the mulank is how you meet the day, the bhagyank is the shape of the road: the work that keeps finding you, and the lesson that keeps coming back until it is learned.
Name number
Your name number is the Chaldean value of the name you actually go by, reduced to a single digit. It is not what you were born with — it is what you have been called since, which is why it describes reception rather than character: how a room adjusts to your name before it has met you. Change the name you use and this number changes with it.
Chaldean, not Pythagorean
Name numbers here use the Chaldean values — the older system, and the one Indian numerology works in. It assigns 1 to 8 and leaves 9 unassigned, holding it sacred. Pythagorean numerology runs 1 to 9 straight down the alphabet and will give you a different answer for the same name; neither is a corruption of the other, they are two conventions, and a page that quotes one without saying which is not telling you enough to check it.
What about 11, 22 and 33?
Western numerology stops reducing at 11, 22 and 33 and treats them as master numbers. Indian numerology reduces them — 11 becomes 2, 22 becomes 4. These pages follow the Indian convention and show the reduced number, but the calculator flags a master total when your date produces one, so you can read it either way rather than being told your number does not exist.