This is a great math study app suitable for the entire elementary school spectrum. Mathaliens covers addition, subtraction, multiplication and division, and has two play modes: Mathaliens Bingo and Hunting Mathaliens, with three levels of difficulty (Easy, Medium, Hard).
In Mathaliens Bingo, a Bingo field is presented with an array of twenty numbers. A math problem is presented, and the player must select the correct answer from the field while striving to get a "Bingo", a horizontal or vertical line of correct answers. Each time a correct answer is selected, the number is replaced by a spunky-looking alien. Scoring depends on how quickly the correct answer is selected; 50 points are attainable within the first second and 5 points are subtracted every second thereafter. Incorrect answers deduct 50 points from the totals. High scores are retained in a list accessible from within the app.
Hunting Mathaliens consists of five levels of progressing difficulty which must be passed through by correctly answering math problems. Two initial lives are given; one life is deducted when a question is answered incorrectly, and an additional life is granted each time a level is completed. In each subsequent level, answer times are shorter and the number of available answers increases. The minimum time for answering in the final level can be adjusted in the settings. A Mathalien is caught and stored in a Mathalien gallery accessible by the My Mathaliens button.
I highly recommend this app as a fun way to practice and sharpen "head math" skills.