Universal Day

“You must not overlook the vibration of the Universal Day number. This can be determined by adding the numbers of the date together, and then reducing them to a single digit. For example, if today is November 8, 2017, the calculation would be as follows:

• 11 + 8 + 2017 = 2036
• 2 + 0 + 3 + 6 = 11 or 2 (1+1=2)

This makes it a 2 Calendar Day.”

source: https://shirleytwofeathers.com/The_Blog/bythenumbers/universal-day-number/

This appears to be similar to how Pythagorean Numerology calculates the Life Path Number.