Math Division Rules for Numbers 1 – 20: Simple Tricks to Remember

                How do you find whether a number is exactly divisible by another number? By performing division calculation? No, you cannot do that for every number. That’s why we need to follow math division rules. These are useful to solve divisibility questions. These rules are also useful to check if a number is Prime. Suppose you want to find 45647845631214566461 is come under numbers divisible by 3 or not. You cannot perform division calculation because it takes lot of time. This is where you need divisibility rules. These rules make your division easy. Here, divisible rules for different numbers with examples under each divisibility rule is explained and generalized rules for division by any number is also included at the end.
Contents
1. What does divisibility mean
2. Divisibility rules for numbers 1 – 20
3. Generalized rules for division
Math division rules for 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20 - Puzzles9

What does divisibility mean

Divisible by” means when you divide one number with another number the result should be whole number with zero remainder.
Ex :
6/3 = 2 ; 6 is divisible by 3, because result 2 is whole number and remainder is 0.
7/3 = 2.33 ; 7 is not divisible by 3, because result 2.33 is not whole number and remainder is 1.

How To Find a Prime Number with maths aptitude tricks

                How to find if a number is prime? We get questions on this topic in some competitive exams. Deciding whether a number is prime number or not is not a simple task if it is bigger number. So, some techniques are needed to tell if the number is prime. This is what you are looking for? then you are in right place to learn how to find prime numbers easily. Because we have covered everything you need to know about Prime numbers.
Contents
1. What does prime number mean?
2. What is prime factorization – Calculating prime factors
3. Finding all prime numbers between 1 and 100 in a simple way
4. How to find a prime number – Prime number check
5. Some facts about prime numbers
6. List of all prime numbers upto 1000
 How To Find a Prime Number with aptitude tricks

What does prime number mean?

A Number which is divisible by 1 and the number itself is called as PRIME NUMBER.
Prime number must be a positive integer and it should be greater than 1.
Examples :
 
17 is divisible by 1 and 17 only, So, it is prime number.
15 is divisible by 1,3,5,15. So, it is not prime number.

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Basic Number Theory for Problems on numbers in Aptitude

         Hi everyone, you may not get direct questions on this in any aptitude type test. But, by knowing this number system basics you can be able to solve some silly questions on numbers in some simple tests. So, Get your basics brushed up with this.
0,1,2,3,4,5,6,7,8,9 –    Digits

group of digits        –    Numbers

basic number theory for number problems

Natural numbers : 1,2,3,4,5,6,7,8,9,10,11………………….
Whole numbers : 0,1,2,3,4,5,6,7,8,9,10,11,12…………….
Integers: ………-4,-3,-2,-1,0,1,2,3,4………………….
        Positive integers : 1,2,3,4,5,6,7………….
        Negative integers : ………….-7,-6,-5,-4,-3,-2,-1
        Non positive integers : 0,-1,-2,-3,-4…….
        Non negative integers : 0,1,2,3,4,5,6…………………

0 is neither positive nor negative.

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