1 + 1/3 - (1/2 + 1/3) - (3/4 - 5/12 + 1/6)=
1 + 1/3 - (1/2 + 1/3) - (3/4 - 5/12 + 1/6)=
$1+\frac{1}{3}-\big(\frac{1}{2}+\frac{1}{3}\big)-\big(\frac{3}{4}-\frac{5}{12}+\frac{1}{6}\big) $ =
= $ 1+\frac{1}{3}-\big(\frac{3+2}{6}\big)-\big(\frac{9-5+2}{12}\big) $ =
= $ 1+\frac{1}{3}-\frac{5}{6}-\frac{6}{12} $ =
= $ 1+\frac{1}{3}-\frac{5}{6}-\frac{1}{2} $ =
= $\frac{6+2-5-3}{6}$ =
= $\frac{0}{6}$ =
= $0$
1 + 1/3 - (1/2 + 1/3) - (3/4 - 5/12 + 1/6)=
= (3 + 1)/3 - (3 + 2)/6 - (9 - 5 + 2)/12 =
= 4/3 - 5/6 - 6/12 =
= 4/3 - 5/6 + 1/2 =
= (8 - 5 - 3)/6 = 0
1 + 1/3 - (1/2 + 1/3) - (3/4 - 5/12 + 1/6) =
= 4/3 - (3+2)/6 - (9-5+2)/12 =
= 4/3-5/6-1/2 =
= (8-5-3)/6 = 0/6 = O