1. (1/5×3/4)×2/3=3/20×2/3=1/10=10
2.2/9×(3/10×7/8)=2/9×21/80=1/3×7/40=7/120
3.15/19×(19/25×7/9)×5/7=15/19×133/225×5/7=15/19×19/45=
=1/3
4.(10/13×11/12)×(12/55×13/20)=55/78×78/550=1/10
1. (1/5×3/4)×2/3=3/20×2/3=1/10=10
2.2/9×(3/10×7/8)=2/9×21/80=1/3×7/40=7/120
3.15/19×(19/25×7/9)×5/7=15/19×133/225×5/7=15/19×19/45=
=1/3
4.(10/13×11/12)×(12/55×13/20)=55/78×78/550=1/10