Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to create an inequality with a solution of x<4 Source: Annie DeAngelo

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to make the product as close to 1,000 as possible. Source: Ellen Metzger

Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to make both expressions factorable. Source: Jack Assaf

Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to make a true fraction division sentence. Source: Shanelia Rhome-Shannon and Aiden (Student)

Directions: Using the digits 0 to 9 at most one time each and choosing either multiplication/division or addition/subtraction, place a digit in each box to make a true statement. Source: Brian Errey

Directions: Using the digits 0 to 9 at most one time each and as many leading zeros as you like, place a digit in each box to create two similar triangles. Source: Drew Ross

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

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

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to create three different linear equations whose y-intercepts have integer values. Source: Michelle Kovesi and Harold Jacobs

Directions: Using the digits 1 to 9 at most one time each, place a digit in each box to find the largest/smallest possible sum of the three terms in this finite geometric series? Source: Dana Harrington