How was trade done earlier?

The some Age man was not aware of any trading. They hunted for their own requirements, later they started cultivating fields. When the wild animals became scarce in a particular area or the crop was bad, tribes moved forwards. Eventually, people came across the other groups that cultivated and produced different things-an exchange of goods started. For the exchanged of goods, the value of the goods had to be determined. This could not be done without numbers, measures, and weights. Scales and calculating devices such as the Abacus were invented, the trading activity expanded and a real triangular trade arose.