如图所示望采纳
4/7×54-16×3/5+27×6/7+1/5×3=4/7×2×27-16×3/5+27×6/7+3/5=8/7×27++27×6/7-(16×3/5-3/5)=27×(8/7+6/7)-(16-1)×3/5=27×2-15×3/5=54-9=45