Пример дроби 7/16-(3/4-5/16)
7/16-(12/16-5/16)=0 ..
7/16-(3/4-5/16)=7/16-(3*4/4*4-5/16)=7/16-(12/16-5/16)=7/16-(12-5/16)=7/16-7/16=0