6.5X23十6.5X67十65=6.5X100=650
6.5×23+6.5×67+65=6.5×(23+67+10)=6.5×100=650
6.5×23+6.5×67+65=65×2.3+65×6.7+65=65×(2.3+6.7+1)=65×10650
6.5×(23+67)+65=650+65=715