Directions: Using the integers 1 to 10, at most one time each, place an integer in each box to make the equation true. Source: Richard Hung

Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to make the equation true. Source: Shaun Errichiello

Directions: Using the integers 1 to 10, at most one time each, place an integer in each box so that the sum is equal to 1. Source: Joshua Nelson

Directions: Using the digits 1 to 6, at most one time each, place a digit in each box to make the largest (or smallest) number that rounds to 5. Source: Annie Forest

Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to make the trigonometric equation true. Source: Kevin Rees

Directions: Using the digits 1 to 9, place a digit in each box to make the answer closer to 200 than 300. Source: Marilyn Burns and Graham Fletcher

Directions: Find three fractions whose product is -5/24. You may use fractions between -8/9 to 8/9 no more than one time each. Find at least 2 possible combinations. Source: Al Oz

Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to create the smallest (or largest) whole number quotient. Source: Ellen Metzger

Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to and make the greatest/least product. Source: Nanette Johnson

Directions: Using the digits 1 to 9, at most one time each, place a digit in each box to make the biggest/smallest product. Source: Nanette Johnson