Mathematics
Why does a negative times a negative equal a positive? Think of it in terms of action and debt. If a negative number represents a debt, then multiplying by a negative number represents the removal of that debt. (Hint: If someone takes away (–) four of your debts that are each worth ₹3 (that is, –3), you are effectively ₹12 richer! Therefore, (–3) × (–4) = +12.)
Whole Numbers
2 Likes
Answer
A negative number represents a debt (an amount owed) and a negative multiplier represents the removal (taking away) of those debts.
Consider the following situation :
Suppose I have 4 debts, each worth ₹3.
Each debt is represented as -3.
If someone takes away (removes) these 4 debts, I am no longer in debt and my wealth effectively increases by ₹12.
Mathematically :
⇒ (-3) × (-4)
⇒ +12.
So, removing 4 debts of ₹3 each makes me ₹12 richer.
Hence, multiplying a negative number by a negative number gives a positive number, because removing debts increases wealth.
Answered By
1 Like
Related Questions
We know that Natural Numbers are closed under addition (the sum of any two natural numbers is always a natural number). Are they closed under subtraction? Provide a couple of examples to justify your answer.
Ancient Indians used the joints of their fingers to count, a practice still seen today. Each finger has 3 joints, and the thumb is used to count them. How many can you count on one hand? How does this relate to the ancient base-12 counting systems?
The temperature in the high-altitude desert of Ladakh is recorded as 4 °C at noon. By midnight, it drops by 15 °C. What is the midnight temperature?
A spice trader takes a loan (debt) of ₹850. The next day, he makes a profit (fortune) of ₹1,200. The following week, he incurs a loss of ₹450. Write this sequence as an equation using integers and calculate his final financial standing.