Increasing Numbers Debrief

Showing other ways to solve the increasing numbers problem shown below.
Let’s call a natural number increasing if each digit as you read from left to right is larger than the digit before it. (E.g. 17, 589, and 13578 are increasing. 903, 43, 7, and 2365 are not increasing.) How many increasing numbers are there?

Math,Logic,Increasing,Numbers,Heuristic,Polya,