如图所示
7/18-7/18x4/5
=7/18x(1-4/5)
=7/18x1/5
=7/90
原式=7/18x(1-4/5)
=7/18x1/5
=7/90
=1/7*1/4 =1/28 二,12分之5÷8分之9×5分之3 =5/12*8/9*3/5 =2/9 三,2又9分之2÷1又8分之3-9分之2×11分之8 =20/9*8/11-2/9*8/11 =(20/9-2/9)*8/11 =2*8/11 =16/11 =1又...
7/18-7/18×4/5
=7/18×(1-4/5)
=7/18×1/5
=7/90