Page 3 - 10.6 - LN

 Brahmagupta’s Rules for Addition (Brāhma-sphuṭa-siddhānta 18.30, 628 CE)

1. The sum of two positives is positive (e.g., 2 + 3 = 5).
2. The sum of two negatives is negative. To add two negatives, add the numbers
(without the signs), and then place a minus sign to obtain the result.
(e.g., (– 2) + (– 3) = – 5).
3. To add a positive number and a negative number, subtract the smaller number
(without the sign) from the greater number (without the sign), and place the sign of
the greater number to obtain the result (e.g., – 5 + 3 = – 2, 2 + (– 3) = – 1
and – 3 + 5 = 2).
4. The sum of a number and its inverse is zero (e.g., 2 + (– 2) = 0). 5. The sum of any
number and zero is the same number (e.g., – 2 + 0 = – 2 and 0 + 0 = 0).

 Brahmagupta’s Rules for Addition (Brāhma-sphuṭa-siddhānta 18.30, 628 CE)

1. If a smaller positive is subtracted from a larger positive, the result is positive

(e.g., 3 – 2 = 1).

2. If a larger positive is subtracted from a smaller positive, the result is negative

(e.g., 2– 3 = – 1).

3. Subtracting a negative number is the same as adding the corresponding positive number
(e.g., 2 – (– 3) = 2 + 3).

4. Subtracting a number from itself gives zero (e.g., 2 – 2 = 0 and – 2 – (– 2) = 0).

5. Subtracting zero from a number gives the same number (e.g., – 2 – 0 = – 2 and 0 – 0 = 0).
Subtracting a number from zero gives the number’s inverse (e.g., 0 – (– 2) = 2)