a)
[tex]10-6+8=4+8=\boxed{12}\\\\10-(6+8)=10-14=\boxed{-4}[/tex]
b)
[tex]10-5\cdot6=10-30=\boxed{-20}\\\\(10-5)\cdot6=5\cdot6=\boxed{30}[/tex]
c)
[tex]8\cdot7-6=56-6=\boxed{50}\\\\8\cdot(7-6)=8\cdot1=\boxed8[/tex]
d)
[tex]24:6\cdot(-2)=4\cdot(-2)=\boxed{-8}\\\\24:(6\cdot(-2))=24:(-12)=\boxed{-2}[/tex]
e)
[tex]-12+4:2-8=-12+2-8=-10-8=\boxed{-18}\\\\(-12+4):2-8=-8:2-8=-4-8=\boxed{-12}[/tex]
f)
[tex]11-8:4-10=11-2-10=9-10=\boxed{-1}\\\\(11-8):(4-10)=3:(-6)=\boxed{-0,5}[/tex]