45*23=
34*5=
3 49-1 56=
5 56+3 34=

1) 8/15
2) 15/4=3 3/4
3) 31/9-11/6=124/36-66/36=58/36=29/18=1 11/18
4) 35/6+15/4=70/12+45/12=115/12=9 7/12

4/5*2/3=8/15
3/4*5=15/4=3,75
3 4/9- 1 5/6= 31/9-11/6=(186-99)/54=87/54=1 33/54
5 5/6 + 3 3/4= 35/6 + 15/4 = (140+90)/ 24=230/24 = 9 14/24 = 9 7/12