Răspuns:
2,(3)=(23-2)/9=21/9=7/3
7/3:4/3=7/3·3/4=se reduce 3 cu 3=7/4
13 si 2/3=(13·3+2)/3=41/3
7/4-{41/3-[11+(3/4+3/4·5/3)]}=
7/4-{41/3-[11+(3/4+5/4)]}=
7/4-[41/3-(⁴⁾11+8/4)]=
7/4-[41/3-(44/4+8/4)]=
7/4-(41/3-52/4)=
7/4-(41/3-³⁾13)=
7/4-(41/3-39/3)=
³⁾7/4-⁴⁾2/3=21/12-8/12=13/12