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MCIII Number Theory 2.22

 
 
JinTina的头像
MCIII Number Theory 2.22
JinTina - 2024年01月4日 Thursday 21:37
 

Hello,

I need some help on this question, I don't really get how to get started.

Thanks,

Tina Jin

 
WangDr. Kevin的头像
Re: MCIII Number Theory 2.22
WangDr. Kevin - 2024年01月6日 Saturday 01:17
 

Try some small numbers to begin with: suppose you want to find all possible $3$ digit numbers with the digits $1,2,3$, and add them up.  What are the numbers, and what is their sum?  More importantly, when you are adding them up, is there any quick way of doing it?

 
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JinTina的头像
Re: MCIII Number Theory 2.22
JinTina - 2024年01月14日 Sunday 09:30
 

Oh! I get it now! I summed up each place value one by one, for example the thousands values are (96/4)(1+2+3+4) since there are 96 numbers and the numbers 1,2,3,4 all appear an equal number of times. I applied similar logic to the hundreds, tens, and ones places to get 259980.

Thanks!

Tina Jin

 
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