Students will learn how to factor and expand the difference of two squares using algebra tiles, then practice doing so. After that, students will see the formula for the difference of two squares and how the formula is derived. Then students will learn why the sum of squares is not factorable. After that, students will practice using the difference formula to factor and expand various expressions. They'll even learn to factor expressions of the form \(a^4 - b^4,\) by applying the difference of squares formula twice, as seen here. Finally, give your students this challenge. Students are unlikely to find the creative step of multiplying both sides by \((4 - 3),\) but the solution is clever and easy to follow, so I think it's worth students trying this problem and seeing the solution.