a)
80 - [ 130 - ( 75 - 11) ]
= 80 - [ 130 - 64 ]
= 80 - 66
= 14
A) \(80-\left[120-\left(75-11\right)\right]=80-\left(120-75+11\right)=80-56=24\)
B) \(12:390:\left[500-\left(125+35+7.30\right)\right]=12:390:\left(500-370\right)=12:390:130=\frac{1}{4225}\)