Memory Span task require test participants to remember a sequence of items and then recall those items in the right order. The app reads betweeen 7 - 40 digits, which you have to enter in backwards order. In psychology and neuroscience, memory span is the longest list of items that a person can repeat back in correct order immediately after presentation on 50% of all trials.To generalize, it refers to the ability of an individual to reproduce immediately, after one presentation, a series of discrete stimuli in their original order. Therefore memory span can be understood as the quantum of action of thought. Digit-span tasks are the most commonly used test for memory span, partially because performance on a digit-span task cannot be affected by factors such as semantics, frequency of appearance in daily life, complexity, etc. Reproduction of the series also involves certain other "reproduction factors," such as language ability and arithmetical proficiency. One of the key aspects of working memory is the ability to inhibit distractions and to focus on stimulus cues. The test is to be performed stepping up and down a step continously. This app is made with according to what I remember myself from taking tests. There are variants of them. but all have the same scope.