45除以[（156+38乘24）除以89]
=45÷[(156+38×24）÷89]
=45÷[(24×6.5+24×38）÷89]
=45÷[24（38+6.5）÷89]
=45÷[（24×44.5）÷89]
=45÷（24×44.5）/89
=45×89/24×44.5
=45/12
=3又3/4