The GRE test includes an unscored section called the “experimental section.” This section can appear randomly in any order after the very first section, i.e., Analytical Writing.
The experimental section can either be Verbal or Quantitative. You will never know which section is the experimental section. Hence, you will try to do your best in every section. The experimental section is not counted towards your total score, so why is it present then?
The purpose of the experimental section is to test the difficulty of new questions that ETS will later use in non-experimental sections of the test. ETS is continually preparing new problems every day because of the high demand for GRE. To include a question on the test, they need to know the difficulty level. They determine this by considering the number of students who got the experimental questions wrong and the average time it took them to answer the questions.