How many numbers are there between 100 and 1000 such that at least one of their digits is 6?  Choose the most appropriate option
A) 648 B) 252 C) 900 D) 1000 E) None of these
Explanation :   numbers between 100 and 1000:=900numbers between 100 and 1000 which do not have digit 6 in any place:=8×9×9=648Unit digit could take any value of the 9 values (0 to 9, except 6)Tens Digit could take any value of the 9 values (0 to 9, except 6)Hundreds digit could take any value of the 8 values (1 to 9, except 6)numbers between 100 and 1000 which have at least one digit as 6:=900−648= 252   Answer : 252
<result>B</result>
How many numbers are there between 100 and 1000 such that at least one of their digits is 6?