Q.1. How many 3-digit numbers can be formed by using the digits 1 to 9
if no digit is repeated?
3-digit numbers have to be formed by using the digits 1 to 9.
Here, the order of digits matters.
Therefore, there will be as many 3-digit numbers as there are permutations of 9 different digits taken 3 at a time.
Therefore, the required number of 3-digit numbers