0.75×1/9+1/8-0.8×3/8

= 75/100 x 1/9 + 1/8 - 8/10 x 3/8 
= 75/900 + 1/8 - 24/80
= 1/12 + 1/8 - 3/10
= 10/120 + 15/120 - 36/120
= 25/120 - 36/120
= - 11/120

koreksi jika ada yang salah

=(0.75x1/9)+1/8-(0.8x3/8)
=0.083+1/8-0.3
=-0.092