PEMDAS
Multiplication:
10* -4 / 3*9 = -40 / 27
Addition:
-40 / 27 + 7/6 find common denominator 108
-40*4 / 27*4 + 7*18 / 6*18
-160 / 108 + 126 / 108
-34 / 108
-17 / 54
Subtract:
-17 / 54 - 2/5 common denominator 270
17*5 / 54*5 - 2*54 / 5*54
-85 / 270 - 108 / 270
-193 / 270
-193/ 270 = -0.7148
-8 / 15 = -0.7148 :)