1.25+0.75+0.75=1+0.25+1-0.25+0.75=2+0.75=2.75
1.25+0.75+0.75=1+0.25+0.75+0.75=1+(0.25+0.75)+0.75=1+1+0.75=2.75
直接算就是最简便的1.25+0.75+0.75= 2+0.75= 2.75
