2.5×6.2+2.5×3.8=2.5×(6.2+3.8)=2.5×10=25
14×(5/6-3/4)÷1/6=14×(5/6-3/4)×6=14×(5-18/4)=14×0.5=7
[3/4-(3/4-1/2)]÷5/8=1/2÷5/8=0.8