What do the letters engraved on the coins of the Roman Empire mean and how do we know them?

What do the letters engraved on the coins of the Roman Empire mean and how do we know them? In addition to the name of the emperor, ancient Roman coins were often included in their titles, and their words are short and these abbreviations have a strong regularity, after mastering the following twenty abbreviations, and then recognizing the names of the emperors, almost all of questions. Here we are trying to understand and know these acronyms SC These are the most common letters The value of the name of the emperor in the copper coin of the Roman Empire is higher than its metal value, which is different from silver and gold coins. Its value is guaranteed by order of the Senate Senatus Consulto or SC. Almost all copper coins made before the late 3rd century AD have the letters "SC" on the reverse. The letters SC on these coins have only slight differences in size and weight, and few changes in other coins. There is no SC on the Roman Bronze Medal, coins after Lucius Domitius Aurelianus, coins minted by Marcus Cassianius Latinius Postumus in the Gaul Empire Mint, copper coins bearing this mark. Some rare coins with engraved letter EX SC. And Senatus Consultum, i.e., the Senate, may make these minted coins out of silver and gold instead of other metals