=0.79×2.5+0.79×7.5=0.79×(2.5+7.5)=0.79×10=7.9注:7.9÷10×0.75×10
7.9✘0.25+7.9✘0.75=7.9x(0.25+0.75)=7.9
0.79×2.5+7.9×0.75=7.9×(0.25+0.75)=7.9×1=7.9