其它
Wendy wrote all the whole numbers from $$13$$ to $$78$$ on her paper. How many times did she write all the digit "$$3$$ on her paper? 
Overseas Competition->Knowledge Point->Counting Modules->Questions Involving Enumeration->Enumeration
Ones: $$13, 23, 33, 43, 53, 63, 73$$  Tens: $$30, 31, 32, 33, 34, 35, 36, 37, 38, 39$$ 