*Tuesday, March 10th, 2015*

There is common perception that Number System questions form the most important part of the CAT syllabus and something that cannot be neglected when it comes to CAT Preparation. While I agree with the latter half, I strongly object to the first part. The perception about Number System is such because when you consider all chapters of CAT Syllabus, It is probably the most important but when you compare it with other categories – it loses its relevance. You have to understand what you are comparing it with. If you are comparing with another chapters like Time, Speed, and Distance or Permutation and Combination – yes, it has more weightage. But if you are comparing it with Arithmetic, Algebra, Geometry, etc. – it is probably the least important part. And because of this incorrect understanding, a lot of students spend a lot of time on Number System. If you are good with Mathematics basics, it wonâ€™t take much time to solve the question depending upon the level of question, but if you are not clear with your basics, you are ending up with an unsolved question, also wasting the important time of 5-7 minutes which can be better utilized elsewhere..

Another issue with Number System questions is that students are not able to decide what is relevant when it comes to preparing for CAT. They spend time sharpening their skills to find out the last two digits, or to understand Fermat Theorem to find out the remainders in Number System questions. If you are preparing for the CAT exam, it is not required at all. Such advanced concepts are not required for CAT Preparation. What you need to do is to practice a sufficient number of questions of each of the areas mentioned below because solving a good number of questions makes sure that you are so far so good clear of the process of solving the questions. The best CAT Coaching institutes and even the CAT coaching faculty, including me, are to blame for this to a certain extent. Given below is the complete list of topics from Number System that you should be familiar with:

Basics of Numbers

Divisibility Rules

Divisibility and Factors

HCF / LCM

Finding Out Last Digit

Finding Out Last Two Digits

Number of Trailing Zeroes

Highest Power of a Number in a Factorial

Finding out Remainders

Base Systems

Integers

Remainders

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You can view the CAT syllabus on complete CAT syllabus here.

**Other posts related to Number System**

How to Find Number of Trailing Zeros in a Factorial or Product

Remainders (Quantitative Aptitude) for CAT Exam Preparation

Determining the second last digit and the last two digits

Factor Theory

Q.1) If the product of three consecutive positive integers is 15600 then the sum of the squares of these integers is

A) 1777

B) 1785

C) 1875

D) 1877

Answer: **See Answer Here With Solution**

Q.2) If a, b, c are three positive integers such that a and b are in the ratio 3 : 4 while b and c are in the ratio 2:1, then which one of the following is a possible value of (a + b + c)?

A) 201

B) 205

C) 207

D) 210

Answer: **See Answer Here With Solution**

Q.3) The numbers 1, 2,â€¦,9 are arranged in a 3 X 3 square grid in such a way that each number occurs once and the entries along each column, each row, and each of the two diagonals add up to the same value.

If the top left and the top right entries of the grid are 6 and 2, respectively, then the bottom middle entry is ?

Answer: **See Answer Here With Solution**

**For More Number System Question With detail Answer and Solutions Click Here**

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Cheers,

Ravi Handa

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