=8.45-9-(2 1/3)-8-(5 1/4)+(3 1/3)
=8.45-9-7/3-8-21/4+10/3
=0.45-9-7/3+10/3-21/4
=45/100-9+10/3-7/3-21/4
=9/20-9+1-21/4
=9/20-8-(21*5)/(4*5)（通分）
=9/20-8-105/20
=-8-96/20
=-8-24/5
=-40/5-24/5
=-(40/5+24/5)
=-64/5
=-12 4/5 (负十二又五分之四）