Question 1026685
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how many four digit codes can be formed using the digits 0,1,2,3,4,5,6,7,8,9 if the last digit 
cannot be 0 or 1 or 2 and repetition of digits is allowed?
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{{{10^3*7}}} = 7000.


Any of 10 digits in the first position;

any of 10 digits in the second position;

Any of 10 digits in the third position,

and any of 7 digits (from 3 to 9) in the fourth position.


It gives that answer.