The General Science section of the test covers earth, space, and physical and life sciences. Because science is such a vast and dynamic topic, focus your study on basic principles. This gives you a good foundation to work through any question that is asked of you. Typical questions may include: “Why is air less dense than water?” or “How do you convert Celsius temperature to Fahrenheit?” The CAT-ASVAB test asks 16 questions in 8 minutes, while the pencil-and-paper version asks 25 questions in 11 minutes.

The categories of the Armed Forces Vocational Aptitude Battery are the following: General Science (GS); Arithmetic Reasoning (AR); Word Knowledge (WK); Paragraph Comprehension (PC); Auto and Shop Information (AS); Mathematics Knowledge (MK); Mechanical Comprehension (MC); Electronics Information (EI); and Sum of Word Knowledge and Paragraph Comprehension (VE).
La Información de automóviles y talleres evalúa la aptitud para el mantenimiento y la reparación de automóviles, y las prácticas de los talleres de carpintería y metales. El examen abarca varias áreas que se suelen incluir en la mayoría de los cursos de automóviles y talleres de las escuelas secundarias, como componentes automotrices, sistemas automotrices, herramientas automotrices, solución de problemas y reparación, herramientas de taller, materiales de construcción y procedimientos de construcción.

You can't use the AR and MK score shown on your ASVAB Score Sheet. The Score Sheet shows "number correct" for your AR and MK Scores, because "number correct" is what is used for job qualifications. However, the military does not use this same score when computing the AFQT. They use the "weighted scores" of the ASVAB sub-tests for AR and MK. Harder questions in these areas get more points than easier questions. The "weighted scores" for AR and WK are not listed on the ASVAB score sheet given to you after the test.
After adding so much information to the aptitude test, there was a bit of difficulty interpreting the test results. In addition to that, a vast majority of test takers were deemed as being under qualified based on their test results. This is why the percentile change was made. It ensured that a 50% actually correlated with a person doing better than 50% of the test takers. Those revisions have worked hand-in-hand with the preparation of the armed forces.