Numbers: 1,2,3,4,5,6,7,8,9
Consider 4 places for the 4 digit number as:
The number has to be even so the units place should be even which can be: 2,4,6,8
The total number of even numbers that can be in units place: 4
Since repetition is not allowed so the total numbers that can be in tenths place is: 9
Similarly, the total numbers that can be in hundredths place is: 9
Similarly, the total numbers that can be in thousandths place is: 9
=> The total number of 4 digit even numbers that are possible from digits 1 to 9 if repetition is allowed are: 9*9*9*4 = 2,916
