7/8-3/8=\frac{4}{8}
12/13-1/13=\frac{11}{13}
7/11-6/11=\frac{1}{11}
25/27-13/27=\frac{12}{27}=\frac{4}{9}
3i1/2-1/2=3
3\frac{14}{15}-\frac{6}{15}=3\frac{8}{15}
8i3/10=…niedokończone
8\frac{3}{5}-1\frac{1}{5}=7\frac{2}{5}=7,4
7\frac{5}{9}-5\frac{4}{9}=2\frac{1}{9}