This is a fantastic website to challenge strong middle school and high school students with math riddles. However, many learners will need adult support because the riddles are deliberately challenging and solutions are not provided directly on the site. Students access riddles from a simple navigation panel where riddles are classified according to difficulty and topic. There are four levels of difficulty from easy to very challenging and nine topics including geometry, algebra, probability and logic. All of the problems may be difficult for many students. An example of an easy riddle is "What is the smallest 3-digit palindrome divisible by 18? Can you solve this without brute force examination?" The site has a very simple design. Riddles are presented one on a page and are typically only a few sentences long. There is no look-up option for unfamiliar terms, but students can easily search the web for vocabulary they do not know. The site is designed to encourage students to try hard to work through the answers on their own. As such, only some puzzles have hints, and users are warned that comments may include solutions. For a site-provided solution, users must email and wait for a promised reply within 24 hours. Overall, this is a wonderful site to find challenging problems for eager students, but less interested students may feel intimidated by the content and not have the intrinsic motivation to work for the solutions.

• Provides sufficient and varied types of practice problems to maximize understanding and generalization of the targeted skill/concept
• Manufacturer claims alignment with Common Core/Known Standards
• Presents educational concepts accurately
• Explains answers so students can learn from mistakes
• Better for teaching the skill to new or struggling learners
• Better for practicing or refreshing the skill
• Skills are practiced through authentic, meaningful problems (not just rote practice)

• Appropriate for a broad age range to use and enjoy
• Subject matter and problems are relevant, interesting and authentic to students
• Visually appealing to children in the target age range
• Provides virtual rewards or incentives after meeting specified goals or objectives
• Provides a "break activity" between academic problem sets
• Offers ongoing, progressive challenge
• Overall - Enjoyable. Given the option, students would choose this option

• Has a free or trial version
• Provides teaching guidance for adults to support the child and set appropriate goals
• Provides an age-appropriate tutorial/first time users can work independently
• Student should be able to use independently after first use
• Has a multi-player option to foster in-person collaboration or cooperation
• Multiple users can save a profile
• Student graduates to the next level or topic only after meeting a benchmark
• Can play without sound and not distract others
• Students can save work between sessions
• Can effectively understand and monitor student's progress (email report or in product)
• Requires registration before using the first time
• Provides options to play in languages other than English/Good for ELL
• Presents information in multiple formats (voice over, pictures and text, etc.)
• Overall - Easy to use

• Numerical Fluency
• Student will need to copy or write multi-digit math problems
• Word problems assume additional knowledge (conversion factors, formulas, symbols, etc.)
• Organization
• Includes long written questions or text that students must be able to read on their own