2,31+17,65-8,69=19,96-8,69=11,27
0.387+(12.613-9.142)=0,387+3,471=3,858
7.891+3.9-(16.01-2.109)=7,891+3,9-13,901=11,791-13,901= -2,11
14537-(2.145+5.392)=14537-7,537=14529,463
15.302+7.879-1.321=23,181-1,321=21,86
28.243+27.17-2.713=55,413-2,713=52,7