Part (i): $(-12) \times 5$ Step 1: Identify the signs: a negative number (debt) multiplied by a positive number (fortune). Step 2: Apply Brahmagupta's law: the product of a debt and a fortune is a debt, so the result is negative. Step 3: Multiply the magnitudes: $12 \times 5 = 60$. Step 4: The final answer is $-60$.

Part (ii): $(-8) \times (-7)$ Step 1: Identify the signs: a negative number (debt) multiplied by a negative number (debt). Step 2: Apply Brahmagupta's law: 'the product of two debts is a fortune' ($- \times - = +$), so the result is positive. Step 3: Multiply the magnitudes: $8 \times 7 = 56$. Step 4: The final answer is $+56$.

Part (iii): $0 - (-14)$ Step 1: Identify the operation: subtracting a negative number (a debt). Step 2: Apply Brahmagupta's law: subtracting a debt is the same as adding a fortune (removal of a debt makes you richer). Step 3: Calculate: $0 + 14 = 14$. Step 4: The final answer is $14$.

Part (iv): $(-20) \div 4$ Step 1: Identify the operation: dividing a negative number (debt) by a positive number (fortune). Step 2: Apply Brahmagupta's law: just as the product of a debt and a fortune is a debt, the division of a debt by a fortune results in a debt (negative). Step 3: Divide the magnitudes: $20 \div 4 = 5$. Step 4: The final answer is $-5$.