FiveThirtyEight’s weekly Riddler column has a really nice problem today:

From Joseph Converse, a puzzle of digital manipulation:

Imagine taking a number and moving its last digit to the front. For example, 1,234 would become 4,123. What is the smallest positive integer such that when you do this, the result is exactly

doublethe original number? (For bonus points, solve this one without a computer.)

Here is the solution… **(spoiler warning!)**

Continue reading Solution to the FiveThirtyEight Riddler Classic puzzle for March 23, 2018