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Problem 32


Problem 32


Pandigital products

We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once; for example, the 5-digit number, 15234, is 1 through 5 pandigital.

The product 7254 is unusual, as the identity, 39 × 186 = 7254, containing multiplicand, multiplier, and product is 1 through 9 pandigital.

Find the sum of all products whose multiplicand/multiplier/product identity can be written as a 1 through 9 pandigital.

HINT: Some products can be obtained in more than one way so be sure to only include it once in your sum.


全数字的乘积

如果一个n位数包含了1至n的所有数字恰好一次,我们称它为全数字的;例如,五位数15234就是1至5全数字的。

7254是一个特殊的乘积,因为在等式39 × 186 = 7254中,被乘数、乘数和乘积恰好是1至9全数字的。

找出所有被乘数、乘数和乘积恰好是1至9全数字的乘法等式,并求出这些等式中乘积的和。

注意:有些乘积可能从多个乘法等式中得到,但在求和的时候只计算一次。