Question 956945: How many distinct four-digit numbers can be formed using only the digits 1, 2, 3, 4 and 5? Assume also that no digit may be used more than once. Please calculate the exact value.
Found 2 solutions by Fombitz, Emilia:
Answer by Fombitz(32388)   (Show Source):
Answer by Emilia(1)  (Show Source):
You can put this solution on YOUR website! Ok, so first you have to think about how many of those five digits can be in the thousands of the four digit numbers. The answer is 5, because the number can be 1235,2341,3245,4321,5321... It can start with all five of the digits given.
Then is the hundreds of the numbers can be only 4, because each digit has to only be used once and we already used one of the five digits in the thousands place.
In the tens place there can be 3 different digets as we already used two and the digets must not repeat.
And in the ones place we can us two different digets.
So the answer will be 5x4x3x2=120
I hope this helped!
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