25分之80×11分之9+25分之16×11分之80
=(80/25)*(9/11)+(16/25)*(80/11)
=(80*9+16*80)/(25*11)
=80*(9+16)/(25*11)
=80*25/(25*11)
=80/11
15分之4×28+15分之11×31
=4×28/15+11×31/15
=(4×28+11×31)/15
=453/15
25分之80×11分之9+25分之16×11分之80
=(80/25)*(9/11)+(16/25)*(80/11)
=(80*9+16*80)/(25*11)
=80*(9+16)/(25*11)
=80*25/(25*11)
=80/11
15分之4×28+15分之11×31
=4×28/15+11×31/15
=(4×28+11×31)/15
=453/15