Friday, February 14, 2020

NUMBER SYSTEM


                 NUMBER SYSTEM
Natural Numbers:
Numbers which we use for counting the objects are known as natural numbers. They are denoted by ‘N’
N = {1,2,3,4,…….}
Whole Numbers:
When we include ‘zero’ in the natural numbers, it is known as whole numbers. They are denoted by ‘W’.
W= {0,1,2,3,4,5,………}
Prime Numbers:
A number other than 1 is called a prime number if it is divisible only by 1 and itself.
If you want to test whether any number is a prime number or not, take an integer larger than the approximate square root of that number. Let it be ‘x’. test the divisibility of the given number by every prime number less than ‘x’. if it not divisible by any of them then it is prime number; otherwise it is a composite number (other than prime).
Example:  Is 349 a prime number?
The square root of 349 is approximate 19. The prime numbers less than 19 are 2, 3, 5, 7, 11, 13, 17.
Clearly, 349 is not divisible by any of them. Therefore, 349 is a prime number.
Composite Numbers:
A number, other than 1, which is not a prime number is called a composite number.
e.g. 4, 6, 8, 9, 12, 14 ...... and so on
Even Number:
The number which is divisible by 2 is known as an even number.
e.g. 2, 4, 8, 12, 24, 28 ...... and so on
It is also of the form 2n {where n = whole number}
Odd Number:
The number which is not divisible by 2 is known as an odd number.
e.g. 3, 9, 11, 17, 19 ...... and so on
Consecutive Number:
A series of numbers in which each is greater than that which precedes it be 1 is called a series of consecutive numbers.
e.g. 6, 7, 8 or 13, 14, 15, 16 or, 101, 102, 103, 104
Integers:
The set of numbers which consists of whole numbers and negative numbers is known as a set of integers it is denoted by 1.
e.g. I = {-4,-3,-2,-1,0,1,2,3,….}
Rational Number:
When the numbers are written in fraction, they are known as rational numbers. They are denoted by Q.
e.g. a/b  are called rational numbers.
Or, the numbers which can be written in the form a/b {where a and b are integers and b is not equal to 0} are called rational numbers.
Irrational Numbers:
The numbers which cannot be written in the form of p/q are known as irrational numbers (where p and q are integers and q is not equal to 0).
Real Numbers:
The numbers both rational and irrational numbers are called real numbers


Thursday, February 13, 2020

FIND THE UNIT DIGIT

1)Find the unit digit of (142)41 + (613)16
A)1
B)2
C)3
D)4
2)Find the digit of (723)427 x (519)315 x (436)62 x (613)16
A)1
B)2
C)3
D)6
3)What is the unit digit of 15 + 25 + 35 + ………+205
A)0
B)5
C)2
D)4
4)Find the unit digit of 376!
A)0
B)2
C)6
D)8
5)If the unit digit of (433 x 456 x43N) is (N+2), then what is the value of N ?
A)1
B)8
C)3
D)6
6)If the unit digit of (239 x346 x34N) is (N+6) , then what is the value of N ?
A)1
B)2
C)4
D)7
7)What is the unit digit of sum of first 121 natural numbers ?
A)1
B)2
C)3
D)4
8)If N=1+11+111+1111+……+111111111 then what is the sum of the digit’s of N ?
A)45
B)18
C)36
D)5
9)What is unit digit of 16 + 26 + 36 + ….. + 206?
A)0
B)1
C)2
D)4
10)What is the unit digit of (67)25-1
A)6
B)8
C)0
D)3


Important Short Tricks To Find Unit Digit of Powers

Some previous year questions asked in CTET Exams are listed below:
(a) Find the Units Place in (567)98 + (258)33 + (678)67
(b) What will come in Units Place in(657)85 - (158)37
These questions can be time-consuming for those students who are unaware of the fact that there are shortcut methods for solving such questions.
Finding the Unit Digit of Powers of 2
First of all, divide the Power of 2 by 4.

If you get any remainder, put it as the power of 2 and get the unit digit

If you don't get any remainder after dividing the power of 2 by 4, your answer will be (2)which always give 6 as the unit digit

Let's solve a few Examples to make things clear. (1) Find the Units Digit in (2)33
Sol -
Step-1:: Divide the power of 2 by 4. It means, divides 33 by 4.
Step-2: You get remainder 1.
Step-3: Since you have got 1 as a remainder, put it as a power of 2 i.e (2)1.
Step-4: Have a look at the table, (2)1=2. So, Answer will be 2
Finding the Unit Digit of Powers of 3
First of all, divide the Power of 3 by 4.

If you get any remainder, put it as the power of 3 and get the unit digit

If you don't get any remainder after dividing the power of 3 by 4, your answer will be (3)which always give 1 as the unit digit
Let's solve few Examples to make things clear.(1) Find the Units Digit in (3)33
Sol -
Step-1:: Divide the power of 3 by 4. It means, divide 33 by 4.
Step-2: You get remainder 1.
Step-3: Since you have got 1 as a remainder , put it as a power of 3 i.e (3)1.
Step-4: Have a look on table, (3)1=3. So, Answer will be 3
(2) Find the Unit Digit in (3)32
Sol -
Step-1:: Divide the power of 3 by 4. It means, divide 32 by 4.
Step-2: It's completely divisible by 4. It means, the remainder is 0.
Step-3: Since you have got nothing as a remainder, put 4 as a power of 3 i.e (3)4.
Step-4: Have a look on table, (3)4=1. So, Answer will be 1
Finding the Unit Digit of Powers of 0,1,5,6

The unit digit of 0,1,5,6 always remains same i.e 0,1,5,6 respectively for every power.

Finding the Unit Digit of Powers of 4 & 9
In case of 4 & 9, if powers are Even, the result will be 6 & 4. However, when their powers are Odd, the result will be 1 & 9. The same is depicted below.
If the Power of 4 is Even, the result will be 6

If the Power of 4 is Odd, the result will be 4

If the Power of 9 is Even, the result will be 1

If the Power of 9 is Odd, the result will be 9.

For Example - 
(9)84 = 1

(9)21 = 9

(4)64 = 6

(4)63 = 4

Finding the Unit Digit of Powers of 7
First of all, divide the Power of 7 by 4.

If you get any remainder, put it as the power of 7 and get the unit digit

If you don't get any remainder after dividing the power of 7 by 4, your answer will be (7)which always give 1 as the unit digit

Let's solve few Examples to make things clear.
(1) Find the Units Digit in (7)34
Sol -
Step-1:: Divide the power of 7 by 4. It means, divide 34 by 4.
Step-2: You get remainder 2.
Step-3: Since you have got 2 as a remainder , put it as a power of 7 i.e (7)2.
Step-4: Have a look on table, (7)2=9. So, Answer will be 9
(2) Find the Unit Digit in (7)84
Sol -
Step-1:: Divide the power of 7 by 4. It means, divide 84 by 4.
Step-2: It's completely divisible by 4. It means, the remainder is 0.
Step-3: Since you have got nothing as a remainder , put 4 as a power of 7 i.e (7)4.
Step-4: Have a look on table, (7)4=1. So, Answer will be 1

Finding the Unit Digit of Powers of 8
First of all, divide the Power of 8 by 4.

If you get any remainder, put it as the power of 8 and get the unit digit

If you don't get any remainder after dividing the power of 8 by 4, your answer will be (8)which always give 6 as the unit digit

Let's solve few Examples to make things clear.(1) Find the Units Digit in (8)34
Sol -
Step-1:: Divide the power of 8 by 4. It means, divide 34 by 4.
Step-2: You get remainder 2.
Step-3: Since you have got 2 as a remainder, put it as a power of 8 i.e (8)2.
Step-4: Have a look on table, (8)2=4. So, Answer will be 4
(2) Find the Unit Digit in (8)32
Sol -
Step-1:: Divide the power of 8 by 4. It means, divides 32 by 4.
Step-2: It's completely divisible by 4. It means, the remainder is 0.
Step-3: Since you have got nothing as a remainder, put 4 as a power of 8 i.e (8)4.
Step-4: Have a look on table, (8)4=1. So, Answer will be 6

Wednesday, February 12, 2020

Syllabus ctet2020


C tet 2020