2.5*2.5+2.5*7=2.5*(2.5+7)=2.5*9.5=2.5*10-2.5*0.5=25-1.25=23.75
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=2.5*(2.5+7)=2.5*9.5=2.5*(10-0.5)=2.5*10-2.5*0.5=25-1.25=23.75