H : W : D       

9 + 4 + 2 = 15



1 + 5 = 6



6 + 9 = 15



1 + 5 = 6



6 × 9 = 54



5 + 4 = 9



× 4 = 36



3 + 6 = 9



× 2 = 18



1 + 8 = 9 […]