Problem #PRU-73741

Problems Number Theory Numeral systems Decimal number system Methods Pigeonhole principle Pigeonhole principle (other)

Problem

An infinite sequence of digits is given. One may consider a finite set of consecutive digits and view it as a number in decimal expression, whose digits shall be read from left to right, as usual. Prove that, for any natural number n which is relatively prime with 10, you can choose a finite set of consecutive digits which gives you a multiple of n.