Task: To learn algebra utilizing the Khan Academy app, I would like to add a pre-algebra course.
Steps:
click back page button at the screen 
click back page button at the screen 
click on edit icon at left side center of the screen to add pre algebra 
click on edit icon at left side center of the screen to add pre algebra 
click on see all (33)  button at upper center of the screen 
choose fourth option ( pre algebra) at the screen
click on done button at lower center of the screen