How many trailing Zeroes does 53! + 54! have?
53! + 54! = 53! + 54 * 53!
= 53! (1 + 54)
= 53! * 55
I know there are 12 trailing zeros in 53! because i can find how many 5s there are in 53! using the method we were taught. But according to answer there is one more 5 in 55. How and why??