Hello everyone! In today's 100-day challenge in the cryptocurrency world, we will discuss the Bitcoin double spending problem. This is one of the core issues that blockchain technology needed to address in its early design. The double spending problem directly relates to the security and credibility of digital currency. Today, let's understand what the double spending problem is and how Bitcoin addresses this challenge!

Reused checks📄
Imagine you buy a computer with a check, and then you attempt to use the same check to buy a mobile phone. If the banking system has a flaw that fails to detect this behavior, it results in 'double spending'.