Where could you find negative numbers?

Answer 1

• If an altitude above sea level is positive, then an altitude below sea level is negative.
• If having money is positive, having a debt is negative.
• If gaining money is positive, losing money is negative (a negative gain).
• If an increase in speed is a positive acceleration, a decrease in speed is a negative acceleration.
• Any other similar case, where you define one thing as positive, and its opposite as negative.