1/4:[5/4-2/3(2,25-1,5)]=
1/4:(5/4-2/3×0,75)=
1/4:(5/4-0,5)=
1/4:(1, 25-0,5)=
1/4:0,75=
1/4:75/100=
1/4×100/75=
25/75=1/3