1 2/3 / 2 1/2 - 3/5 X 9/7

( 1 2/3 : 2 1/2 ) - ( 3/5 x 1 2/7 )
= ( 5/3 : 5/2 ) - ( 3/5 x 9/7 )
= ( 5/3 x 2/5 ) - 27/35
= 10/15 - 27/35
= 350/525 - 405/525
= -55/525
= -11/105