adult arithmetic problems

I am an adult who has also done a lot of math here. I definitely use paper and pencil. Actually, after I had been doing problems here for about a month, I realized that the iPad and web platforms have what is variously called a scratchpad or a sketchpad by various users. In the bottom left corner of a problem, there's a squiggly icon. If you click on it, it brings up a left menu of a color pallette, an eraser, and on the web site but no longer in the iPad app, an undo tool.

Since I am an adult learner who does not need to answer to a teacher, coach, parent, or guardian, I do take some Khan Academy practices/exercises/quizzes/tests "open notes" or look at videos to refresh my mind on a particularly difficult question. In fact, the latter "strategy" is encouraged here because the option to view a video on a subject without the penalty of getting the problem marked wrong (unlike when hints are requested) is available most of the time.