Ответ:

1 1/3×4=4/3×4/1=16/3=5 1/3

7 2/3×6=23/3×6=138/3=46/1=46

8×3 1/4=8×13/4=8/1×13/4=2/1×13/1=2×13=26

21 2/9×9=191/9×9=191/9×9/1=191

2 3/4×5/6=11/4×5/6=55/24=2 7/24

7/13×5 1/5=7/13×26/5=7/1×2/5=14/5=2 4/5

8/17 ×3 2/5=8/17×17/5=8/1×1/5=8/5=1 3/5

3/5×1 5/6=3/5×11/6=1/5×11/2=11/10=1 1/10

3 1/2× 4 2/3=12 2/6=12 1/3

12 1/3× 1/5=12 1/15

9/50×27/18=1/50×27/2=27/100

1 5/7×14/36=12/7×14/36=1/1×2/3=2/3