The **digital root** of a number is obtained by adding together the digits of that number, and repeating that process until a number is arrived at that is less than \(10\).

For example,for \(29953\) the **digital root** is \(29953 \rightarrow 28\rightarrow 10\rightarrow 1\).

Let \(S\) be the number of all positive integers *less* than **one million** that have a **digital root** of \(1\). What is the **digital root** of \(S\)?

Check out part 2 for a more challenging version

×

Problem Loading...

Note Loading...

Set Loading...