How many zeros are at the end of (100!)(200!)(300!) when multiplied out?
The number of 0s are the number of 10s in the factor.
This is also the number of 2 and 5s.
But because there are always gonna be more 2s than 5s, we just need to count the number of 5s.
For example in 10!, there are 2 fives. One 5 from 5 and one 5 from 10.
So 10! has 2 zeros.
Try counting the number of 5s.
Good luck. :)))
If you need more help, just ask.