Parikarmāṣṭaka - Fundamental Operations

Introduction

Arithmetic deals with calculations using numbers. Pāṭīgaṇita is the Samskrit word for arithmetic and geometry .Pāṭīgaṇita is formed by combining the words Pāṭī (slate) and gaṇita (mathematics). Since gaṇita was done using a board of a slate , it was called Pāṭīgaṇita. For all transactions using numbers will require the basic operations of addition, subtraction, multiplication, division, squaring etc. Ancient Indian Mathematicians mentioned eight fundamental operations together called as Parikarmāṣṭaka.

Definition

Parikarma means arithmetic operations and aṣṭaka means group of eight. Parikarmāṣṭaka signifies eight basic operations.

The eight fundamental operations are  :

1. Saṅkalanam (addition)
2. Vyavakalanam (subtraction)
3. Guṇana (multiplication)
4. Bhājana (division)
5. Varga (squaring)
6. Varga-mūla (square root)
7. Ghana (cubing) and
8. Gana-mūla (cube root)

Addition and subtraction form the basis of all calculations. Bhāskara I mentions in the below shloka

संयोगभेदा गुणनागतानि शुद्धेश्च भागो गतमूलमुक्तम् ।

व्याप्तं समीक्ष्योपचयक्षयाभ्यां विद्यादिदं द्व्यात्मकमेव शास्त्रम् ॥ (Āryabhaṭīya-bhāṣya in Gaṇitapāda, p.43)

"All arithmetical operations resolve into two categories though usually considered to be four. The two main categories are increase and decrease. Addition is increase and subtraction is decrease. These two varieties of operations permeate the whole of mathematics. Multiplication and evolution ( square etc,) are particular kinds of addition; and division and involution( square root etc) are particular kinds of subtraction. Indeed every mathematical operation will be recognised to consist of increase or decrease. Hence the whole of this science should be known as consisting truly of these two only."

Saṅkalana and Vyavakalana (Addition and Subtraction)

Addition is the first fundamental operation in mathematics. Subtraction is the reverse of addition.

Bhāskara II has mentioned about these operations in his work on Līlavatī.

कार्यः क्रमादुत्क्रमतोऽथवाऽङ्कयोगो यथास्थानकमन्तरं वा ॥ (Līlavatī , vs.12, p.12)

"The addition or subtraction (of digits in the given numbers) is to be done place wise right to left or left to right."

Write the given numbers one below the other so that the digits are aligned to their place value. Then starting with the units place add or subtract the digits, later move to tens and so on.

Samskrita names for Addition - yoga (addition), saṃyoga (sum), saṃyojana (joining together) , saṃyuti (sum), saṃyuti (sum), saṇkalana (making together).

Guṇana (Multiplication)

The multiplication of whole numbers is repeated addition. For example :

$2\quad X\quad 4=2+2+2+2=8$

Samskrita names for Multiplication - āhati (multiplication), ghāta (product), [guṇana , hanana, hati, vadha] (multiplication).

2	X	4	=	8
↑		↑		↑
guṇya (multiplicand)		guṇaka (multiplier)		guṇana-phala (Result of Multiplication)

Methods of Multiplication :

• Rūpa-guṇana - Direct Method
• Khaṇḍa-guṇana - Split Method
• Bhakta-guṇana - Factor Method
• Sthāna-vibhāga-guṇana - Place wise multiplication
• Iṣṭonayug-guṇana (Adding or subtracting a desired number)

Rūpa-guṇana - Direct method :

Here the tables of multiplier should be known. Multiplier is taken as a whole.Each digit of multiplicand is multiplied by the multiplier to get the product. In this method, the multiplier is taken a whole since it is small.

Example: 234 X 5 =

(1) (2)

2 3 4

x 5 =

1 1 7 0

Khaṇḍa-guṇana - Split Method :

Here the multiplier is split into sum of two numbers . This is represented as below.

a X b = a X (c + d) = (a X c) + (a X d) where b = c + d.

This is the distributive property of multiplication over addition.

Example: 234 X 16 = 234 X (10 + 6 ) = (234 X 10) + (234 X 6) = 2340 + 1404 = 3744

Bhakta-guṇana - Factor Method :

Here the multiplier is split into product of two numbers. This is represented as below.

a X b = a X (c X d) = (a X c) X d where b = c X d

Example: 234 X 16 = 234 X (8 X 2) = (234 X 8) X 2 = 1872 X 2 = 3744

Sthāna-vibhāga-guṇana - Place wise multiplication :

Multiply the multiplicand by each digit of the multiplier separately. Place them appropriately one below the other . Add those numbers. This method is the standard method of doing multiplication.

Example: 234 X 16

2 3 4

X 1 6 =

1 4 0 4

+ 2 3 4 =

3 7 4 4

Iṣṭonayug-guṇana (Adding or subtracting a desired number) :

The Samskrit word Iṣṭonayug is a compound word consisting of iṣṭa , ūna , yuk which means respectively 'desired, minus and plus'.

इष्टोनयुक्तेन गुणेन निघ्नोऽभीष्टघ्नगुण्यान्वितवर्जितो वा । (Līlāvatī, vs.16, p.15)

"Add or subtract any convenient number to the multiplier and multiply it. Then multiply by the added or subtracted number and subtract or add this product from the previous one."

Add any desired number to the multiplier to get a convenient round figure. Then multiply the multiplicand with the round figure and the added number. Then subtract the products to get the final answer.

or

Subtract any desired number from the multiplier to get a convenient round figure. Then multiply the multiplicand with the round figure and the subtracted number. Then add the products to get the final answer.

Example:

234 X 16 = 234 X (20 - 4) = (234 X 20) - (234 X 4) = 4680 - 936 = 3744

234 X 16 = 234 X (10 + 6) = (234 x 10) + (234 x 6) = 2340 + 1404 = 3744

Tatstha-guṇana

Ancient Indian Mathematicians enhanced the several methods for multiplication to perform multiplication more efficiently and easily. Tatstha-guṇana is one of those methods making multiplication involving three or more digits faster. Indian Mathematicians like Śrīdhara, Mahāvīra, Śripati have mentioned this method. Tatstha-guṇana is also known as vajrābhyāsa.