How many more books do you need to read over the summer if you already read 4 books and, you need to read a total of 16 books? Write an equation to represent this situation and solve the equation using mental math. O 16 = b = 4: b = 4 more books O4 × b = 16; b = 4 more books O4+16= b; b = 20 more books O4+b= 16; b = 12 more books​