1)(3 1/7+2 1/3)÷3 2/7=1 2/3
_3 1/7+2 1/3=3 3/21+2 7/21=5 10/21
_5 10/21÷3 2/7=115/21×7/23=5/3×1/1=5/3=1 2/3
2)3 1/13×(2/9+1 4/5)=6 2/9
_2/9+1 4/5=2/9+9/5=10/45+81/45=91/45=2 1/45
_3 1/13×2 1/45=40/13×91/45=8/1×7/9=56/9=6 2/9
3)(13 7/12-10 2/3)÷2 1/2=1 1/6
_13 7/12-10 2/3=13 7/12-10 8/12=12 19/12-10 8/12=2 11/12
_2 11/12÷2 1/2=35/12÷5/2=35/12×2/5=7/6×1/1=7/6=1 1/6