CLASS 4 MATH

CONTENTS OF THIS PAGE:

Face value and Place value

Long form or expanded form (how to write in long form or expanded form in Mathematics)

Practice Sheet

Short form (how to write in short form in Mathematics)

Practice Sheet

Factors and Multiples

Practice Sheet

Least Common Method  LCM using COMMON MULTIPLE METHOD

LCM  using PRIME FACTORISATION METHOD

LCM using COMMON DIVISION METHOD

HCF  Highest Common Factor Prime Factorisation Method

HCF Common division method

Practice Sheet for HCF and LCM

FACE VALUE: It is the digit itself.

PLACE VALUE: It is the place in which the digit lies.

LONG FORM OR EXPANDED FORM

In this method, we split the given number by writing the  face value of the digit followed by so many number of zeros based on the place value and expand it as shown below.  

Ones place or units place  - Face value of the digit (the digit itself)

Tens place - Face value of the digit followed by one zero

Hundreds place - Face value of the digit followed by two zeros

Thousands place - Face value of the digit followed by three zeros

Ten Thousands place - Face value of the digit followed by four zeros

Lakh place - Face value of the digit followed by five zeros

Ten lakh place - Face value of the digit followed by six zeros

Crore place - Face value of the digit followed by seven zeros

Ten crores place - Face value of the digit followed by eight zeros

Let us see some examples:

237895  = 200000 + 30000 + 7000 + 800 + 90 + 5

14506534 = 10000000 + 4000000 + 500000 + 6000 + 500 + 30 + 4

PRACTICE SHEET:

Write in long form:

1. 25008

2. 3210075

3. 11523

4. 980706

5. 6302005

SHORT FORM

In this method, we write the numbers one below the other in the decreasing order of their place value and then add them to get a single number as shown below.

   20000

+   4000

+      300

+         60

+            5

------------

   24365

------------

300000+ 40000 + 6000 + 700 + 40 + 9 = 346749

20000000 + 3000000 + 8000 + 500  + 40 + 6 = 23008546 

PRACTICE SHEET:

Write in short form:

1. 5000+300+40+6

2. 700000 + 80000 +1000 + 900 + 90 +6

3. 50000 + 200 + 1

4. 6000 +600 +60 + 6

5. 90000000+8000000 + 700000 + 60000 + 5000 + 400 + 30 + 2

FACTORS AND MULTIPLES:

Factor is a number that exactly divides another number without any remainder.  1 is a factor of all numbers since it divides any number without leaving any remainder.  This leads to the fact that every number is a factor of itself.

Let us take 12. 

12 = 1 x 12

           2 x 6

           3 x 4

12 is written as a product of two different numbers in every step.  Each and every number in the above list is called a factor of 12. Therefore, the factors of 12 are 1, 2, 3, 4, 6 and 12. 

So, to find the factor of any number,  start with 1 and continue in the increasing order of numbers giving the same product and stop when a pair of numbers is repeated. In the above list, we stopped with 3 x 4 as the next pair in order will 4 x 3.

Multiple of a number is the result obtained when that number is multiplied by another number. Multiplication table is formed when this number is multiplied with numbers 1, 2,3,.... in a sequential manner. Let us take the number 3. So the multiples of 3 are 3 x 1 = 3, 3 x 2 = 6, 3 x 3 = 9,...

PRACTICE SHEET

1, Find the factors of 

1. 24

2. 36

3. 45

4. 60

5. 72

6. 96

7. 100

8. 120

9. 150

10. 216

2. Write the first five multiples of the following numbers:

1. 5

2. 9

3. 12

4. 15

5. 28

6. 30

7. 32

8. 48

9. 50

10. 90

PRIME FACTORISATION:

Prime factorisation is the method in which a number is expressed as the product of its prime factors. Let us see some examples:

HIGHEST COMMON FACTOR (HCF)

HCF of two numbers is the highest factor that is common to both the numbers.

METHOD 1

Prime Factorisation Method

METHOD 2

COMMON DIVISION METHOD

In this method, we start dividing the numbers with prime factors that are common to all of them and  stop dividing when there is no factor common to all the numbers left out. Let us take an example to explain this.

In the example given above, we started with prime factors common to all the three numbers. We find that the last step 1, 2, 4 has no common factor. So we stop with this. The product of all the common factors is taken as the HCF. Here the HCF is 2 x 2 x 2 x 2 x 3 =48. 

TO RECALL TOPICS GO TO THE PREVIOUS PAGES BY CLICKING BELOW

METHOD 3 

LCM USING COMMON DIVISION METHOD:

In the above common division method discussed for  HCF,   the division process is stopped when numbers do not have any other common factor.  But fpr LCM, the division process is continued till we get 1 in the final step for all the numbers. The product of all the factors thus obtained will be the LCM.