1、7.625-19/3+5.75-11/8
=（7又3/8-11/8）+5.75-19/3
=6+5又3/4-6又1/3
=5又3/4-1/3
=5又5/12
2、2×4.6×9+4×9.2×18/（1×2.3×4.5+3×6.9×13.5）
=1×2.3×4.5×（4+8）/[1×2.3×4.5×（1+3）]
=12/4
=3