Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to create a true statement. Source: Katelyn Devine

Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to to create a true statement. Source: Paige Sheehan

Directions: Using the values 8, 10, 12, 14, 16, 18, and 20, determine lengths for an acute triangle, a right triangle, an obtuse triangle, and a non-triangle. Source: Jonathan Lees

Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to create a true statement Source: Dwight Stephenson

Directions: The three triangles on the line are similar. Using the digits 0 to 9 at most one time each, place a digit in each box for the legs of the right triangles. Source: Jay Sydow

Directions: Using the digits 1 through 9 at most one time each, fill in the boxes to create a rectangular prism with a volume that is greater than 100 cubic units. What’s the least volume? What’s the greatest volume? Source: Kari Frazier

Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to create a true equation. Source: Jos Bertemes

Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to create a true statement. Source: Matthew Miller

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to create the largest (or smallest) sum possible. Source: Annie DeAngelo

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to make a correct equation. Source: Stephen Cox