[Maths Class Notes] on Factor of 105 Pdf for Exam

Pair Factors of 105

We will find the pair factors of 105 by multiplying the two numbers in a pair that will eventually give the original number 105.

Positive Pair Factors of 105 are

(1,105)

(3, 35)

(5, 21)

(7, 15)

(15, 7)

(21, 5)

(35, 3)

(105, 1)

Negative Pair Factors of 105

(-1,-105)

(-3, -35)

(-5, -21)

(-7, -15)

(-15, -7)

(-21, -5)

(-35, -3)

(-105, -1)

All Factors of 105 in Pairs

Here, you can see  all factors of 105 in pairs

(1,105) are factors of 105 as 1 x 105 is 105

(3, 35) are factors of 105 as 3 x 35 is 105

(5, 21) are factors of 105 as 5 x 21 is 105

(7, 15) are factors of 105 as 7 x 15 is 105

Factor Tree of 105

One method to find the prime factorization of a number is to make a factor tree. In factor trees, the factors of numbers are first recognised and then those numbers are further factorised until we reach closure. 

The find step of constructing a factor tree is to find the pairs of a factor whose product of the numbers we are factoring. These two factors are the first branch of the factor tree. There are generally various pairs of factor factors that we chose to initiate the process. We repeat the process with each factor until every branch of the tree ends in a prime number.

Here, you can see the factor tree of 105

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Solved Examples

1. Find the prime factorization of 700 and 100 and then find the prime factorization of 7000 knowing that 7000 = 100 x 70.

Solution: Prime factorization of 700 and 100 are

All prime factors of 700 = 2 x 5 x 7

All prime factors of 100 = 2 x 2 x 5 x 5

Knowing the fact that 7000 = 100 x 70 to find the prime factorization of 7000.

7000 = 100 x 70 = 22 x 52 x (2 x 5 x7) = 2 x 2 x 5 x 5 x 2 x 5 x 7 = 23 x 53 x 7

2.  Find the common factor of 6 and 8

All factors of 6 = 1, 2, 3 and 6

All factors of 8 = 1, 2, 4 and 8

Hence, the common factors of 6 and 8 are 1 and 2.

3.  What is the prime factorization of the following numbers?

28, 32, and 100

Prime factors of 28 are = 2 x 2 x 7 = 22 x 7

Prime factors of 100 are = 2 x 2 x 5 x 5 = 22 x 55

Prime factors of 32 are = 2 x 2 x 2 x 2 x 2 = 25

Fun Facts

• All the natural numbers are a minimum one pair factor.

• 1 is the factor of each and every number. For example, 1 x 6= 6, 1x 13= 13, 1 x 63 = 63

• In division, divisor and quotient are both considered as the factors of the dividend if the remainder is 0.

Quiz Time

1. Which of the below is the factor of 72?

1.  8 and 9

2. 12 and 7

3. 36 and 36

4. 9 and 7

5. None of these

2. How many pair factors are there for the number 28?

1. 1

2. 2

3. 3

4. 4

3. The common factors of 56 and 44 are

1. 1,2,4

2. 1,2,11

3. 1,8

4. 2