How many digits have to be written in order to write down every number from $$1$$ to $$100$$ inclusive? ($$2007$$ Math Kangaroo Problem, Level $$3-4$$, Question \#$$23$$) 
Overseas Competition->Knowledge Point->Word Problem Modules->Page Number Problem->Correspondence between Numbers and Page Numbers->Applying the Total Number of Numbers
$1$-digit numbers: $9\times1=9$ digits.  $2$-digit numbers: $90\times2=180$ digits.  $3$-digit numbers: $1\times3=3$ digits.  Total: $9+180+3=192$. 