Simplify the following text for a Grade 10 native English-speaking person.
Original: The Clay Mathematics Institute has called this one of the seven most important open problems in mathematics and has offered a US$ 1,000,000 prize for a solution or a counter-example .
Simplified: The Clay Mathematics Institute has called this one of the seven most important open problems in mathematics , and offered a US$ 1,000,000 prize ( approx .