有趣數學問題

2007-02-24 4:47 am
show that 99999999 x 12345679 is a palindrome (hint: consider a x (b+c) = ab + ac)
A palindrome is a number that reads the same forward and backward eg: 484, 121, 12321.
更新1:

opps.....I thought of that solution ages already but it's not good enough to act as an explanation......is there someone wiser who can give me a simpler answer????(so I don't need to work the whole thing out for missus to see)

回答 (2)

2007-02-24 5:33 am
✔ 最佳答案
99999999 x 12345679
=(100000000 - 1) x 12345679
= 1234567900000000 - 12345679
= 1234567887654321
2007-02-24 5:36 am
12345679 x 99999999

=(1000000000 - 1) x 123456789

=123456789000000000 - 123456789

=12345678876543211

2007-02-24 01:21:10 補充:
sorry...睇錯題目,請參考其他解答.
參考: BY EASON MENSA


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