1.properties:six cards on which different numbers are printed.
Performing methods:
add the number in secret on the top left corner of the cards which audience picked out,then you will get the number of his/her ages,for example,if the audience is 30-year-old,and there are four in the six cards are printed 30, and the number on the top left comer of each card is 2,4,8 and 16, you will know the age of this audience after you add these numbers