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For all positive integers n, the expression n! denotes the product of the first n positive integers. When 5! is expressed as an iteger, what is the ones digit?

2007-09-23 13:16:21 · 3 answers · asked by Anonymous in Science & Mathematics Mathematics

3 answers

0

Since it includes the factors 2 and 5, it has to be divisible by 10.

2007-09-23 13:26:05 · answer #1 · answered by Computer Guy 7 · 0 0

0. Because 5! = 5*4*3*2*1 = 120

Notice that the last digit is going to be 0 for any higher values of n too, because having the "5" and "2" in the factors means it's always going to be a factor of 10, and all factors of 10 end in 0.

2007-09-23 20:20:54 · answer #2 · answered by Anonymous · 0 0

Yes, it would be 0. 5 Factorial = 5*4*3*2*1
5*4*3*2*1
20*3*2*1
60*2*1
120*1
120

The last digit would be 0.

2007-09-23 20:25:16 · answer #3 · answered by Me.. 4 · 0 0

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