8=20+7

8=2+7-1=12+7 (2nd solution by John Stokes)
8=2/2+7
8=3+7-2=(.7-.2)-3=3/.2-7=2*(7-3) (2nd and 3rd solutions by Adam S.)
8=2(7-4)=4/(.7-.2) (2nd solution by Adam S.)
8=2*.5+7
8=2*7-6
8=7/.7-2 (Roger Bessette) 
8=7+.2+.8 (Adam S.)
8=(7+9)/2=(7+.2)/.9

8=2(10-7)
8=(11-7)*2

8=13-7+2

Statement of the problem