202020reglen
202020reglen, also known as the 2020 rule, is a mathematical curiosity that has gained attention due to its unusual properties. The rule states that for any four-digit number, if you subtract the number formed by the first two digits from the number formed by the last two digits, and then multiply the result by 1111, you will always get the original four-digit number. For example, for the number 2020, subtracting 20 from 20 gives 0, and multiplying by 1111 gives 0, which is not the original number. However, for the number 2021, subtracting 20 from 21 gives 1, and multiplying by 1111 gives 1111, which is the original number.
The rule can be expressed mathematically as follows: for a four-digit number ABCD, where A, B, C,
The rule was first discovered by a mathematician named John Conway, who shared it on his blog
While the rule is a mathematical curiosity and has no practical applications, it has become a popular