1, ( 6 ) : ( 3 - 5 / 3 ) =
( 16 - 1 ) / 9 : ( 3 / 1 - 5 / 3 ) =
15 / 9 : ( 9 / 3 - 5 / 3 ) =
5 / 3 : 4 / 3 =
5 / 3 × 3 / 4 =
15 / 12 = 5 / 4
