Master some basic mental math skills and tricks. It's all about practice and mastery. The skills are easy to learn and understand, but practice is required for mastery. Mastery is considered 20 problems (mentally) in 60 seconds. With this sampler, you can master (1) adding 1-digit numbers; (2) multiplying and dividing by 5; (3) multiplying by 11; (4) multiplying the number 1 through 20; All Mentally! NO Paper! NO Pencil! There are three levels of play so you start at beginner and grow to advanced, as the problems grow more and more difficult. A complete log of your progress is maintained for your review. This is the introductory sampler to the Mental Math Series of Apps, each available for $1.99. Give it a try - we're sure you'll get hooked!