1)5,8÷7,2=58÷72=0.80(5)=0.81
2)5/9+3/8=40/72+27/42=67/42=1 15/43
3)0.81+ 1 15/43=81/100+1 15/43=3483/4300+ 1
1500/4300=1 4983/4300=2 683/4300=2 1/6
4)1,323÷2.1 =13.23÷21=0.63
5)0.63+1.245=1.875
6) 2 1/6÷1,875= 13/6÷1875/1000=(13×1000)÷(6×1875)=0.8
ответ:0.8