Challenge 24 is a mathematics game in which competitors use multiplication, addition, subtraction and division in various combinations to manipulate four numbers on a card to equal 24. The Trumbull County Educational Service Center and the Tribune Chronicle hold their annual Challenge 24 Tournament in the Fall.Challenge 24 is open to students in grades 4-8 in Trumbull County public, private and parochial schools. Students participate in four divisions: grade 4 in Division 1; grade 5 in Division 2; grade 6 in Division 3 and grades 7&8 in Division 4.