27/34 * (5-2 4/5*1 1/9) 2 1/7*3 1/9 3/7*7/9 5/8*1 13/15*2 2/7 решите все 4 примера нужно

1) 12/17
2)2/21
3)1/3
4)13/42

27/34×(5-2 4/5×1 1/9)=27/34×(5-14/5×10/9)=
=27/34×(5-28/9)=27/34×(45/9-28/9)=27/34×
×17/9=3/2=1,5
2 1/7×3 1/9=15/7×28/9=5/1×4/3=20/3=6 2/3
3/7×7/9=1/1×1/3=1/3
5/8×1 13/15×2 2/7=5/8×28/15×16/7=1/1×4/3×2/1=
=8/3=2 2/3