Digit Span
Memorize the numbers, then type them back in order.
About this game
Digit Span is a classic working memory task used in neuropsychology since the early 20th century. The average adult span is 7 ± 2 forward, and 5 ± 1 backward.
In Forward mode, type back the digits in the order shown. In Backward mode, reverse them — significantly harder. The game increments span until you fail.