Online Course Discussion Forum

Return to: Site

MCIII Number Theory 2.22

 
 
Picture of Tina Jin
MCIII Number Theory 2.22
by Tina Jin - Thursday, January 4, 2024, 9:37 PM
 

Hello,

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

Thanks,

Tina Jin

 
Picture of Dr. Kevin Wang
Re: MCIII Number Theory 2.22
by Dr. Kevin Wang - Saturday, January 6, 2024, 1:17 AM
 

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?

 
Show parent
Picture of Tina Jin
Re: MCIII Number Theory 2.22
by Tina Jin - Sunday, January 14, 2024, 9:30 AM
 

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

 
Show parent