Math CentralQuandaries & Queries


Question from gina, a parent:

i am having a hard time figuring this out.. i believe the answer is 3105 but the 0 is throwing me off... i am a 4 digit number between 3100 and 3200, none of my digits are even, the sum of my digits is 9, the largest digit is in the ones place, what number am i ??

Hi Gina,

The zero should through you off. Zero is even so it can't be one of the digits.

The number is between 3100 and 3200 and the digits are all even so it can't be 3200 and hence the first two digits must be 3 and 1. The sum of the digits is 9 so the last two digits must have a sum of 5. The sum of any two odd numbers is even so there are not two odd digits which have a sum of 5. There is no number that satisfies the requirements of this problem.

I hope this helps,


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