Sell Nintendo DS Games. Get Cash for Challenge Me Maths Workout. Challenge Me: Maths Workout! Challenge Me: Maths Workout is the second game to be released in the Challenge Me series after Challenge Me: Brain Puzzles. Incorporating two number puzzle games, Challenge Me: Maths Workout will not only bring you hours of fun and relaxation, it may also improve your Maths skills. Hidden Logic! In hidden logic you must guess the value of your opponent's cards whilst stopping them from guessing yours. Initially the cards are facedown on the Nintendo DS screen – a correct guess (from 1-11) will reveal the card. Play to reveal all of your opponents cards before they reveal yours! Formulate! Formulate! is a numbers game that uses equations and cards to formulate answers. Each card, numbered 1-9 is also associated with a mathematical symbol such as +, - , x or ÷. You must move the cards around the screen to create a correct formula. Formulate! is a great way to sharpen up your arithmetic skills while relaxing at home or battling the hordes on the tube or bus!