5 out of 8 × 9 out of 1 × 5 out of 4

5 out of 8 × 9 out of 1 × 5 out of 4

5 of 8 × 9 of 1 × 5 of 4
=(5 / 8 × 4 / 5) × 1 / 9
=1 / 2 × 1 / 9
=1 out of 18