12 years back, on my way back home from DC, I used to post a puzzle almost every week. Doing the same today.

A little background… This week, in Chicago, Deval gave me a little gift. Apparently, she was in a store that sells calendars and came across a calendar that a math problem for each day. Somehow I came to her mind!!

And this is the first problem I saw on the cover page.

You remember mod right? It is the remainder remaining after you do a division. So 27 mod 6 would be 3.

The puzzle is:

15¹¹³ mod 113 = ?