What it means
Take the day of the month and add its digits until one remains: born on the 29th, 2 + 9 = 11, 1 + 1 = 2, so the Mulank is 2. Only the day matters, which is why everyone born on the 5th, 14th or 23rd of any month shares a Mulank.
How it is read
Indian numerology reads it first and treats it as temperament — the register a person operates in day to day, and the one other people notice. Each digit is assigned a graha: 1 the Sun, 2 the Moon, 3 Jupiter, 4 Rahu, 5 Mercury, 6 Venus, 7 Ketu, 8 Saturn, 9 Mars.
What to watch for
Numerology is not part of classical Jyotish. The digit-to-planet mapping is the standard Indian convention, but it was grafted on from the Chaldean and Pythagorean traditions rather than derived from the Sanskrit texts, and schools disagree on the finer rules. Read a number as a description, not a forecast.