3/5乘2/5除3/5乘2/5=3/5×2/5÷3/5=3/5×2/5×5/3=3/5×5/3×2/5=2/5
14.2乘99+14.2=14.2×(99+1)=14200
(1/4+5/6-1/3)乘12=1/4×12+5/6×12-1/3×12=3+10-4=9
3/5乘2/5除3/5乘2/5=3/5×2/5÷3/5=3/5×2/5×5/3=3/5×5/3×2/5=2/5
14.2乘99+14.2=14.2×(99+1)=14200
(1/4+5/6-1/3)乘12=1/4×12+5/6×12-1/3×12=3+10-4=9