If I am given 10 math problems, and I can and do solve the first nine in the same way, I may struggle with the tenth problem if it requires a different method to solve it. This best illustrates the concept of

This shows the concept of mental sets. Mental sets is the tendency to approach a problem in a definite method because it was previously worked on before but this can be an obstacle to problem solving because it can hinder one's capacity to make alternative solutions, if given a different problem.