### Hi anonymous.

To find the number of trailing zeros you can use a computer program like the one below adapted  from http://www.geeksforgeeks.org/count-trailing-zeroes-factorial-number/ by following the instructions found here:  https://en.wikipedia.org/wiki/Trailing_zero.

// Function to return trailing 0s in factorial of n
// http://www.geeksforgeeks.org/ count-trailing-zeroes-factorial-number/
function findTrailingZeros($n) { // Initialize result$count = 0;
// according to https://en.wikipedia.org/ wiki/Trailing_zero
$i=5; while(floor($n/$i) >= 1) {$count += floor($n/$i); $i=$i*5;}
return floor(\$count);
}
}


The code above is written in PHP, but can be translated easely to many other computer languages.

It was adapted from the code below. I don't remember very well, but there is a issue with the original code shown below.

// C++ program to count trailing 0s in n!
#include <iostream>
using namespace std;
// Function to return trailing 0s in factorial of n
int findTrailingZeros(int n)
{ // Initialize result
int count = 0;
// Keep dividing n by powers of 5 and update count for (int i=5; n/i>=1; i *= 5)
count += n/i;
return count;
}


You can also check this calculator factorial calculator here (click). As you can see, the number of trailing zeros in 70 factorial is 16.