Ответ:\(8.7+2.3=11\)\(15.6-7.4=8.2\)\(10.5\cdot4.2=44.1\)\(6.3-0.3=6\)\((3.4+1.5)\cdot2=4.9\cdot2=9.8\)Ответ: 1) 11; 2) 8,2; 3) 44,1; 4) 6; 5) 9,8.