A teacher distributes scorecards to students, if everyone gets $3$ cards, there will be a shortage of $12$ cards. If everyone gets $2$ cards, all these cards will just be divided. Then, how many students are there in total? 
Overseas Competition->Knowledge Point->Word Problem Modules->Distribution Problems->Basic Distribution Problems
If $2-1=1$ less card is given to students, the situation would transfer from \textquotesingle a shortage of $12$ cards\textquotesingle~ to \textquotesingle all cards are just divided\textquotesingle{} . Therefore. the shortage of $12$ cards is equal to the number of cards that everyone gets $1$ less card. So, there are in total $12\div1=12$ students. 