Math Equals Love - Seemingly endless list of games and puzzles relating to every aspect of math and many different difficulty levels.
2048 Puzzle - Addictive number problem-solving puzzle that is appropriate for all ages & builds computational skills.
PreAP Algebra I - Even though we do not use the official PreAP curriculum from College Board, they still have a wealth of resources on their site for free.
National Library of Math Manipulatives - Exactly what it sounds like. Virtual math manipulatives that can be used anytime you would like to use a physical manipulative but you either don't have that object, don't have enough for everyone, or want to let your students practice on their own outside of class.
Numbers: Facts, Figures, & Fiction - Interactive website that gives interesting information about numbers 1-31. Click on the day of the month on the left side of the screen and read all about that number. Divide the information into pieces so you cover something new every month.
TPSP Tasks for 5-8 - TPSP = Texas Performance Standards Projects. This link will take you directly to the high school grade band. From there, choose your subject and explore all the projects they have to offer. Keep in mind, these projects are intended to take weeks to months to complete and follow the complete research and presentation cycle.
Math Maven's Mysteries - Comprehensive list of mysteries linked to specific math concepts. Includes a super helpful teacher's guide with suggestions on classroom use.
Math Prodigy - Kids love this game! Online, interactive, and adaptive, Prodigy Basic is free to use & great for when students finish a task early.
KenKen Puzzles - Super fun and addictive puzzle game that uses basic math operations (add, subtract, multiply, and divide), numbers less than 10, and simple rules to make an incredibly challenging game. Start on 3x3 and let students work their way up.
Tang Math - Math games tied to specific math concepts that allow students to apply their knowledge in new and fun ways.
Figure This! - Collection of math challenges created or curated by the National Council of Teachers of Mathematics (NCTM) and sorted by specific concept or grade level. Suggestions for use in the classroom can be found in the teacher corner (link in top left of screen).
Open Middle Math Problems - Multiple entry points abound in this resource that contains practice problems at every level of math.
Numberless Word Problems - These problems are designed to provide scaffolding to enable students the opportunity to develop a better understanding of the underlying structure of word problems.
Which One Doesn't Belong - Website dedicated to providing thought-provoking puzzles for math teachers and students alike. There are no answers provided as there are many different, correct ways of choosing which one doesn't belong.
YouCubed - Provides research-based teaching methods, mathematics tasks, videos, and ideas to significantly reduce math failure and inequality in the United States and beyond, inspiring teachers and empowering all students to success.
Exploding Dots - See mathematics like you've never seen it before and take part in a global math conversation with your students.
Solve Me Puzzles - Three different math puzzle types of increasing difficulty all centered around basic math operations. Some use negative numbers in the higher levels.
Steve Wyborney - The amazing creator of Splat!, Cube Conversions, and the extremely popular Esti-Mysteries has a fantastic collection of math puzzlers to spark deep math conversations in the most resistant students.
NRich Math - Free curriculum-linked resources to develop mathematical reasoning, and problem-solving skills.