GWD25-37

[CherrieLi]

37.
AB
+ BA
---------
AAC

In the correctly worked addition problem shown, where the sum of the two-digit positive integers AB and BA is the three-digit integer AAC, and A,B, and C are different digits, what is the units digit of the integer AAC?

A.9
B.6
C.3
D.2
E.0

答案E

請問是怎麼推演出來的呢?

[oneseven]

我是用土法煉鋼的方式推出來的

A. C要是9
A和B的組合有(1,8)(2,7)(3,6)(4,5)
算出來的答案都是99 無法得到AAC的結果

就是這樣推的 你可以試試看

[CherrieLi]

嗯, 看來只能用推的方式了......謝謝你喔^^