17.5*13.8-38*1.75+（2-4分之3）*23.3+*（1+4分之1）*6又10分之7
=17.5X13.8-3.8X17.5+1.25X23.3+1.25X6.7
=17.5X(13.8-3.8)+1.25X(23.3+6.7)
=17.5X10+12.5X30
=175+37.5
=212.5