Say you have a $100 debt, so your net worth is -$100. If I take that $100 debt away from you, your net worth goes up by $100. -$100×-1 = +$100: a negative times a negative is a positive.
A debt is a negative quantity, and me taking something from you changes your quantity of whatever it was by a negative amount (if I take one apple from you, you gain -1 apples), so a negative times a negative is a positive.
If you have 3 $100 debts. If I take two of those $100 debts away from you, your net worth goes up by -$100×-2 = $200.
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Say you have a $100 debt, so your net worth is -$100. If I take that $100 debt away from you, your net worth goes up by $100. -$100×-1 = +$100: a negative times a negative is a positive.
A debt is a negative quantity, and me taking something from you changes your quantity of whatever it was by a negative amount (if I take one apple from you, you gain -1 apples), so a negative times a negative is a positive.
If you have 3 $100 debts. If I take two of those $100 debts away from you, your net worth goes up by -$100×-2 = $200.