MathDB

19

Part of 2018 India PRMO

Problems(1)

Infinite 6's

Source:

8/19/2018
Let N=6+66+666+....+666..66N=6+66+666+....+666..66, where there are hundred 6′s6's in the last term in the sum. How many times does the digit 77 occur in the number NN
number theory