14.5-7又八分之7-6又20分之17的和-2.152

①14.5-（7又8/7-6又20/17）-2.125 =14.5+6.85-（7.875+2.125） =21.35-10 =11.35 ②3又5/3×25又5/2+37.9×6又5/2 =3.6×25.4+37.9×6.4 =3.6×25.4+25.4×6.4+12.5×6.4 =（3.6+6.4）×25.4+12.5×8×0.8 =10×25.4+100×0.8 =254+80 =334