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How many of the natural numbers from 1 to 800 inclusive, contain the digit 6 at least once?

 Feb 9, 2021
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All  the  integers  from  600  - 699  contain at least one 6 =  100  numbers

 

In every  100  except  from 600 - 699     we  will  have

 

10 numbers  containing  at at least one  6 from   _60  to _69  =  7 (10) = 70 numbers

 

9(7)  = 63  more numbers   that have an ending  digit of  6

 

So

 

100  +   70   +  63   =   

 

233  numbers contain at least one 6

 

cool cool cool

 Feb 9, 2021

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