原式=7/12*24+3/8*24+23/24*24 =7*(24/12)+3*(24/8)+23*(24/24) =7*2+3*3+23*1 =14+9+23 =46
(7/12+3/8-23/24)*24=7/12*24+3/8*24+23/24*24=14+9+23=46
