Elementary Number Theory Problems. Part V

This paper reports on the formalization of ten selected problems from W. Sierpinski's book "250 Problems in Elementary Number Theory " [5] using the Mizar system [4], [1], [2]. Problems 12, 13, 31, 32, 33, 35 and 40 belong to the chapter devoted to the divisibility of numbers, problem 47 concerns relatively prime numbers, whereas problems 76 and 79 are taken from the chapter on prime and composite numbers.