MathDB

8.5

Part of 2005 All-Russian Olympiad Regional Round

Problems(1)

sum of digits of N, 5N All-Russian MO 2005 Regional 8.5 9.5.

Source:

8/26/2024
It is known that the sum of the digits of the natural number NN is 100100, and the sum of the digits of the number 5N5N is 5050. Prove that NN is even.
number theorysum of digitsEven