Question

1. library: a shelf had books on it. a librarian added 12 more books, bringing the total to 45. how many were there originally?

Explanation:

Step1: Define original book count

Let $x$ = original number of books.

Step2: Set up equation

$x + 12 = 45$

Step3: Solve for $x$

$x = 45 - 12$

Answer:

33