How many different positive integers divisible by 4 can be formed using at least one of the digits 1, 2, 3 and 4 exactly once and no other digits? For example, 12 counts, but 512 does not.
4 {1, 2} | {2, 4} | | {3, 2} |(total: 3) {1, 2, 4} | {1, 3, 2} } | | {3, 1, 2} | | {3, 2, 4} | {4, 1, 2} ... (total: 5)
{1, 3, 2, 4} | {1, 4, 3, 2} | | {3, 1, 2, 4} | | {3, 4, 1, 2} | | {4, 1, 3, 2} | ... (total: 5)
1 + 3 + 5 + 5=14 I get 14 integers divisible by 4
Add 1 as well and make it 15 numbers in total !!.
+1206 
