MathDB
2016 preRMO p13, how many times 2 appears in {1,2,..,1000}

Source:

August 9, 2019
algebranumber theory

Problem Statement

Find the total number of times the digit ‘22’ appears in the set of integers {1,2,..,1000}\{1,2,..,1000\}. For example, the digit ’22’ appears twice in the integer 229229.