2.1*2.6+7.4*5.4+2.6*3.3 =(2.1+3.3)*2.6+7.4*5.4=5.4*2.6+7.4*5.4=5.4*(2.67.4)=5.4*10=540.147*368+0.632*147=147*0.368+0.632*147=147*(0.368+0.632)=147*1=147
楼上是正解