0,4 (2/3+3/5-1/2)-115%=

0,4 = 4/10
115% = 115/100 = 23/20
2/3 + 3/5 - 1/2 = 20 + 18 - 15 / 30 = 23/20

4/10 ( 23/20 ) - 23/20
96/200 - 23/20
96 - 230 / 200
- 134 / 200

Maaf bila (ada yang) salah :)