-1/4+1/8;1/6 (-1/3);-7/13+(-4/26);-0.15+1.3;-0.48+3.6;-3.4+(-2.38)
-1/4+1/8= -2/8+1/8= -1/8 1/6+(-1/3)=1/6-2/6= -1/6 -7/13+(-4/26)=-14/26 - 4/26= - 18/26= -9/13 -0,15+1,3=1,15 -0,48+3,6=3,12 -3,4+(-2,38)=-3,4-2,38= -5,78