Probability
posted by Mack .
Roberto has 10 different colored sheets of paper and 3 different colored envelopes. How many different letters can he make consisting of one colored sheet of paper and one colored envelope??? Please explain!

10 * 3 = ?
If you don't understand draw a picture to represent this problem. 
11. Roberto has 10 different colored sheets of paper and 3 different colored envelopes. How many different letters can he make consisting of one colored sheet of paper and one colored envelope?