Last time, I explained why#BTCis halved every four years. Today, let's talk about why the total amount of BTC is 21 million. In fact, this is a simple math problem. BTC generates a block approximately every 10 minutes (this 10-minute setting should be a technical consideration. If the block is produced too quickly, the consumption will be too high, because for each block, all mining machines have to perform a large number of hash operations. If the block is produced too slowly, it may affect the efficiency of the Bitcoin network). The time for 210,000 blocks is 1458 days and 8 hours, which is about 4 years. Initially, each blockchain rewarded 50 BTC, and the reward was halved every 210,000 blocks, so the total output of the Bitcoin network is equal to 50*210000+25*210000+12.5*210000+…… The limit of the geometric sequence is equal to (50*210000)/(1-0.5)=21 million. In EXCEL, you can list the data and draw charts. In the output chart, we can see that BTC output is a nearly closed graph, and the area of 21 million is not very obvious. The following BTC total amount chart is very obvious, infinitely close to 21 million. The mathematical beauty of BTC!