Odd digits −1,3,7. Even digits −4,6,8
1st place can be filled by 3,4,6,7
Case I: 3 is at 1st place.
3
Since number is even, 4th place can be filled in 3 ways and 2nd place in 3 ways.
Number of ways =1×3×3×3=27
Case II: 4 is at 1st place.
4
Number of ways =1×4×3×2=24
Case III: 6 is at 1st place.
6
Number of ways =1×4×3×2=24
Case IV: 7 is at 1st place.
7
Number of ways =1×1×3×3=9
Hence, total number of ways
=27+24+24+9=84 ways