Math is a vast subject. Hence every competition or job requires a specific  mathematical knowledge and offers a unique math aptitude test. 

Math or Quantitative Aptitude Tests evaluate numerical ability and problem  solving skills of candidates. This test forms the major part of a number of  important entrance exams like JEE, CAT, MAT, SAT, GMAT, CBI, UPSC, SSC  and many other significant exams. Many companies use it in their selection  procedure.  

It is one section which is used to filter out candidates as not everyone has the  skill sets required to sail through this section. On the contrary, aspirants who  are good at it, have a chance to convert it into a highly scoring section and  enhance their chances of cracking the entrance exam. 

HOW TO COMMAND OVER APTITUDE MATH:  

Most of the topics of Math aptitude are from the basic mathematics like: 

Number system, Algebra, Ratio & proportion, Percentage, Profit and loss,  simple interest, compound interest, linear equations, quadratic equations,  statistics, probability, Trigonometry, geometry etc. 

Here if you give attention then find all these topics are from the Math syllabi  from grade 6 to grade 10.  

So key to command over math aptitude is simple to command over math in  each of your respective class. And for this one must need to understand the  thoroughly concept of every topic of math of his/her respective class followed  by a great practice.