## How to solve a hard number system question for CAT confidently and quickly 8

Number system puzzle problem 8: Leftmost digit of a natural number at least 7 digits long is 3. When it is dropped, number becomes one-fifth...Read on.

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Basic concepts on a subject form the foundation. Basics are for building the foundational concepts in concise but comprehensive manner.

In work life and personal life often we need to learn the basics on a subject quickly. Usually it is not easy to acquire the basic concepts on any subject reliably in a short time from a concise material.

Basic concepts on any subject form the foundation, but generally we have found it is not easy to build it in a short time. Our focus here is on **base concepts** in a concise form that can be learned quickly and be used as a launch pad for further learning and subject specific problem solving.

Often we added a **rich concept layer** derived from the base concepts that helps to solve more complex problems with great ease. For us, it is a two layer concept model: Base concepts and Rich concepts derived from base concepts. Objective is efficient problem solving.

* Basic maths:* Basic concepts on maths. The content is primarily targeted for competitive test requirements.

* Reasoning and logic analysis:* Tutorials, problems and puzzles on competitive test reasoning and logic analysis.

Submitted by Atanu Chaudhuri on Fri, 08/01/2021 - 22:55

Submitted by Atanu Chaudhuri on Wed, 06/01/2021 - 22:12

Number system puzzle problem 7: Cube of a number exceeds its product with two other numbers by 2, the cube of the second number is less than...Read on.

Submitted by Atanu Chaudhuri on Tue, 05/01/2021 - 20:50

Solve Number system puzzle problem 6 in 1 min: Product of a 2 digit number and number formed by reversing digits of the first is 2430. Find smaller number.

Submitted by Atanu Chaudhuri on Mon, 04/01/2021 - 12:24

Number System Puzzle Problem 5: If 495 is subtracted from a 3 digit number with its digits reversed, you get the original number. Sum of digits...Read on.

Submitted by Atanu Chaudhuri on Sun, 03/01/2021 - 22:14

Learn how to solve number system puzzle problem 4 in 1 min: The sum of thousands and tens digits in a 4 digit number is 4, the sum of hundreds...Read on.

Submitted by Atanu Chaudhuri on Sun, 03/01/2021 - 16:15

Solve Number System Puzzle Problem 3 in 2 mins: Denominator of a fraction is less than the square of the numerator by 1. If 2 is added to both...Read on.

Submitted by Atanu Chaudhuri on Fri, 01/01/2021 - 18:12

Solve number system puzzle problem 2 in 90 secs: What 2 digit number is less than sum of squares of its digits by 11 and exceeds their doubled product by 5?

Submitted by Atanu Chaudhuri on Tue, 10/11/2020 - 23:41

Solve Number System Puzzle Problem 1 in 180 secs: How many of the four digit natural numbers divisible by 24 have also 24 appearing in them? Can you solve?

Submitted by Atanu Chaudhuri on Thu, 23/07/2020 - 01:20

Secant of a circle relation: Square of a tangent segment from an external point equals product of two segments of a secant of a circle through the point.

Submitted by Atanu Chaudhuri on Tue, 21/07/2020 - 23:48

Incenter of a triangle and Angle bisectors: Segmentation of the opposite side by an angle bisector and Segmentation of the angle bisectors at the Incenter.