What is the largest ten-digit number in which there is at least one smaller digit between every two identical digits? Or: Ida chose a two-digit number without any zeros and multiplied it by the number resulting from swapping the two digits of her chosen number. The result was a four-digit number beginning with 3 and ending with 7. Which of the two numbers Ida multiplied was the larger?
On 13 March, 315 children will compete in 63 teams to solve questions like these. "This makes Graz one of the largest venues for the international Naboj competition in the German-speaking world," reports Michael Fischer, who co-organised the event.
An equal number of ten- to twelve-year-olds competed in mixed-gender pairs on 24 February at the University of Graz. They had to solve 20 problems in 45 minutes. The victory went to St. Marein Middle School.