在计算第三年的NPV时,书中"remaining mortgage balance at payoff is $1450000",

the first year   interest  148000   priciple 8997

the second year            147100               9897

那么第三年的还贷利息应该为  (1480000-8997-9897)*0.1=146111

                                               pricipal   156997-146111=10886

从而三年末remaining mortgage balance at payoff is $1480000-8997-9897-10886=1450220

弄不明白哪里错了呢?