Question

2/3 of all your books are fiction. 1/6 of those are historical fiction. What fraction of all your books are historical fiction?

Answer 1

1/6 because it would equal 5/6 and you have 1/6 left

Answer 2

If 2/3 of the books are
fiction and 1/6 of those are historical fiction, then you have to find what 1/6 of 2/3 is. When you see "of" in an equation, replace it with (×).

1/6 of 2/3 =
1/6 × 2/3 =
2/18 = 1/9

1/9 of all the books are historical fiction.