Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to give this cylinder the maximum volume possible. Source: Kyle Leinweber

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to make a true statement. Source: Owen Kaplinsky

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to make a true statement. Source: Owen Kaplinsky

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to make a triangle with side lengths that give the corresponding area. Source: Owen Kaplinsky

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to create two different solutions to the problem: Source: Noel Chang

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box so that each quadratic is the same. Source: John Rowe

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to create a a system of equations with infinitely many solutions. Source: Mike

Directions: Use only the digits 1-9, each digit only once, create a problem that has the solutions x = 4 and x = -1/2. Source: Amy Herzog

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to create a quadratic equation with an imaginary solution of the form ±𝒃𝒊 where 𝒃 is a whole number. Source: Bradley Springer

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to find the second greatest solution. Source: Neil Hamilton