How many trailing Zeroes does 53! + 54! have?  Options:
A) 12 B) 13 C) 14 D) 15 E) 16
53! + 54! = 53! + 54 * 53!   = 53! (1 + 54)   = 53! * 55   Number of trailing 0s in 53! = number of 5s in the expansion of 53!   = 10 + 2= 
<gadget id="calculator">10 + 2</gadget>
<output>12</output>
12   There is 1 more 5 in 55.   Hence, total number of trailing 0s= 12 + 1= 
<gadget id="calculator">12 + 1</gadget>
<output>13</output>
13   Answer (B).   In most cases, when we are adding multiple terms, all of which have trailing 0s, the sum will have as many trailing 0s as that in the lowest term. Example:  20 + 2300 + 34210000= 
<gadget id="calculator"> 20 + 2300 + 34210000</gadget>
<output>34_212_320</output>
34212320 -&gt; one 0 because lowest term 20 has one 0.   This case has an exception because of an additional 5 in 55. answer is 13
<result>B</result>
How many trailing Zeroes does 53! + 54! have?