a/ \(6,5+1,2+3,5-5,2+6,5-4,8\)
\(=\left(6,5+3,5+6,5\right)+1,2-\left(5,2+4,8\right)\)
\(=16,5+1,2-10\)
\(=17,7-10=7,7\)
b/ \(\left(-4,3.1,1+1,1.4,5\right):\left(-0,5:0,05+10,01\right)\)
\(=1,1\left(-4,3+4,5\right):\left(-10+10,01\right)\)
\(=1,1.0,2:0,01\)
\(=1,1.20=22\)
c/ \(\left(6,7+5,66-3,7+4,34\right).\left(-76,6.1,2+7,66.12\right)\)
\(=\left[\left(5,66+4,34\right)+\left(6,7-3,7\right)\right]\left[7,66.\left(-10\right).1,2+7,66.12\right]\)
\(=\left(10+3\right).\left[7,66\left(-12\right)+7,66.12\right]\)
\(=13.0=0\)