Answer :
$5
If you have 4 books and the total cost is $20, divide!
20/4 = 5
Answer: 5
Explication: If you have 5 and 4 than you have to multiply them. See here, you have 5x4. 5x4= 20
Explication: If you have 5 and 4 than you have to multiply them. See here, you have 5x4. 5x4= 20