सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

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The first term on the right hand side is termed as the
Adhimāsa-graha, and the second term is evidently 13 times
the position of the Sun whereas the term on the left-hand-
side is the Moon’s position. Hence, ignoring the integral
number of revolutions, we have Moon’s position = Adhi-
māsa — graha + 13 times Sun’s position (Ignoring the
number of integral revolutions means subtracting integral
revolutions or adding them if necessary).
Verses 12, 13. A few more examples on the afore-
said principle. The planetary position obtained by the
sum of the sidereal revolutions of two planets, added to or
Subtracted from another planetary position obtained by
the difference of the sidereal revolutions of two planets and
divided by two gives the positions of the two planets res-
pectively, the quicker of the two in the first case and the
slower in the second. Similarly the planetary position com-
puted from the difference of the sidereal revolutions of two
planets subtracted from the planetary position of the quicker
of the two gives the position of the slower whereas the
former planetary position added to the position of the
slower gives the quicker.
Comm. We have [(P₁ + P₂) + (P₁ − P₂)] / 2 = P₁ (1) and
[(P₁ + P₂) − (P₁ − P₂)] / 2 = P₂ (2) where P₁ is the number
of sidereal revolutions of a quick-moving planet and P₂
that of a slow-moving one. Multiplying the above equa-
tions by A/M with the former notation,
[A/M (P₁ + P₂) + A/M (P₁ − P₂)] / 2 = (P₁ × A) / M (3) and
[A/M (P₁ + P₂) − A/M (P₁ − P₂)] / 2 = A/M × P₂ (4)
Equations (3) and (4) mean what has been stated in verse
(12). Again we have the equations P₁ − (