13.7÷12.5÷0.8 3.25×8.4+6.75×8.4 (8.1-5.4)÷3.6+85

1) 13.7÷12.5÷0.8
=13.7÷（12.5×0.8）
=13.7÷10
=1.37
2） 3.25×8.4+6.75×8.4
=（3.25+6.75）×8.4
=10×8.4
=84
3）（8.1-5.4）÷3.6+85.7
=2.7÷3.6+85.7
=0.75+85.7
=86.45