Explanation:
We can start by finding the number of stamps in one book:
Number of stamps in 1 book = 20
To find the number of stamps in 4 books, we can multiply the number of stamps in one book by 4:
Number of stamps in 4 books = 20 x 4 = 80
To find the number of stamps in 12 books, we can use the information given in the problem that there are 380 stamps in 19 books:
Number of stamps in 19 books = 380
Number of stamps in 1 book = 380/19
Number of stamps in 12 books = (380/19) x 12 = 240
Therefore, there are 80 stamps in 4 books, and 240 stamps in 12 books.