The 1st digit can be written in 5 ways The 2nd digit can be written in 4 ways (since 1 already gone and no repetition) The 3rd digit can be written in 3 ways (since 2 already gone and no repetition)
Total number of ways = 5x4x3 = 60 ways
2nd Method : Permutation (since ORDER MATTERS) of 3 digits chosen among 5 (with no repetition)