5 . [(85 - 35 : 7) : 80 + 90] - 50
= 5 . [(85 - 5) : 80 + 90] - 50
= 5 . [80 : 80 +90] - 50
= 5 . [1 + 90] - 50
= 5 . 91 - 50
= 455 - 50 = 405
5 [ ( 85 - 35 : 7 ) : 80 + 90 ] - 50
= 5 [ ( 85 - 5 ) : 80 + 90 ] - 50
= 5 [ 80 : 80 + 90 ] - 50
= 5 [ 1 + 90 ] - 50
= 5 . 91 - 50
= 455 - 50
= 405
=))