Final answer:
Greece used the Greek Drachma before adopting the Euro in 2001 for electronic use and in 2002 for cash. The transition to a common currency such as the Euro can be influenced by economic and policy factors.
Step-by-step explanation:
Before switching to the Euro, Greece used a currency called the Greek Drachma. The Greek Drachma was replaced by the Euro in 2001 for electronic transactions and in 2002 for cash transactions.
Countries decide to switch to a common currency for several potential benefits, such as reducing exchange rate fluctuations and facilitating trade. However, countries might consider reverting back to their own currency due to problems like a lack of control over monetary policy, economic downturns, or a desire to address national economic issues independently.