1.-0.5-（-3又1/4）+2.75-(+7又1/2)=-1/2+13/4+11/4-15/2=13/4+11/4-1/2-15/2=24/4-16/2=6-8=-22. [(2/3-1/2)÷1/30]×(-1/5) =(1/6 *30)*(-1/5)=5*(-1/5)=-1
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