Mrs. Gonzalez baked cookies for her class. After 12 students each ate a cookie, there were 6 left. How many cookies did Mrs. Gonzalez bake?
n - `12 = 6
add 12 to both sides
n - 12 + 12 = 6 + 12
n = 18
add 12 to both sides
n - 12 + 12 = 6 + 12
n = 18