Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · Signs, Planets, Birth
जातकम् १
स्पष्टास्तेंशाः खषट्त्र्यासा गुणयित्वा स्वकैर्गणैः ।वर्षाणि शेषमर्कघ्नं हारात्संमासकाः स्मृताः ॥ १२६ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 55, verse 126.
Multiply those exact degrees by their own years and divide by 360: this gives years. Multiply the remainder by 12 and divide by the same divisor: months.
Simple meaning: Degree parts are turned into years and months by multiplication and division.
तच्छेषश्च त्रिगुणितः तेनैवाप्तं दिनानि च ।
The remainders are turned into days and smaller units.
हित्वा भाज्यंगभागादीन्कलीकृत्य खखाक्षिभिः ।
The rising sign's degrees are turned into minutes and divided to give years.
द्विसप्तांशे च मासादिलग्नायुर्जायते स्फुटम् ।
A step to find the rising sign's life in months, and to start the degree method.