https://doi.org/10.4169/college.math.j.43.1.037 https://www.jstor.org/stable/10.4169/college.math.j.43.1.037 Summary Latin squares form the basis for the recreational ...

I have listed in random order five positive integers, four of two digits and one of one digit. They use each of the digits 1 to 9. None of the two-digit integers has any factor greater than 1 in ...

I have written down three three-digit integers which between them use nine different digits. One of the integers is a perfect square and another is a triangular number. The sum of the three integers ...