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Mental Arithmetic (Posted on 2003-10-05) Difficulty: 3 of 5
I can multiply any three-digit number by 1667 in my head, usually in less than 10 seconds.

Also, to make it even more impressive, I come up with the digits of the result in proper order (not in reverse!)

How can I do this?

See The Solution Submitted by nellie    
Rating: 3.3333 (6 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Another Clarification | Comment 2 of 21 |
I am unsure how this got off the queue without adjustments, but it could be restated as follows:

"If you tell me a 3 digit number, I can tell you what 1667 times it is in my head, usually in less than 10 seconds. I will even start with the most significant digit in the number. How can I do that?"

I am assuming Charlie's idea is right, and that 1000 is being excluded. (because 1667 x 1000 is easy to do)
  Posted by Gamer on 2003-10-05 12:27:18
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