Since repetition is not allowed, we can use permutation for this question.

\(^7_3 P\) = \(\frac{7!}{(7 - 4)!}\) = 210 

OR

Choose the First Digit: 7 options (2-8).
Choose the Second Digit: 6 options remaining.
Choose the Third Digit: 5 options remaining

Total Combinations:

Total = 7 × 6 × 5 = 210.