6. Express the following composite numbers as a product of their prime factors. Use division method.
(a) 108
(b) 124
(c) 100
(d) 275
(e) 240
Answers
Answer:
Step-by-step explanation:
HOW TO EXPRESS A NUMBER AS THE PRODUCT OF ITS PRIME FACTORS
About "How to express a number as the product of its prime factors"
How to express a number as the product of its prime factors :
Prime factorization is the method of expressing a number as a product of prime numbers.
Step 1 :
Put the given number inside the "L" shape
Step 2 :
We have to split the given number by prime numbers only. That is, always we have to put prime numbers out side the "L" shape.
Step 3 :
The tricks given below will be helpful to find the prime number which exactly divides the given number.
A number which ends with 0, 2, 4, 6 and 8 is divisible by the smallest prime number 2.
A number which ends with 0 or 5 is divisible by 5
If the sum of digits of the given number is a multiple of 3, then the given number is divisible by 3.
Step 4 :
Take the first digit of the given number and check how many times the prime number goes in to that.
Further process is explained in the examples given below.
Prime factorization method - Example problems
Example 1 :
Express 324 as the product of prime factors
Solution :
Step 1 :
Since the given number ends with 4, first we have to split the given number by the smallest even prime number 2.
Step 2 :
2 goes into 3 one time.We have 1 left. If we take this 1 along with the next digit 2, we get 12. If we divide this by 2, we get 6.
We don’t have any number remaining in 12. So we can take the next digit 4. Again, if we divide 4 by 2, we get 2.
Step 2 :
If we repeat this process, we will get
So, the prime factors of 324
= 2 ⋅ 2 ⋅ 3 ⋅ 3 ⋅ 3 ⋅ 3
= 22 34
Let us look into next example of "How to express a number as the product of its prime factors".
Example 2 :
Express 625 as the product of prime factors
Solution :
Step 1 :
Since the given number ends with 5, first we have to split it by the prime number 5.
Step 2 :
5 goes into 6 one time.We have 1 left. If we take this 1 along with the next digit 2, we get 12. Again we have to divide it by 5. If we divide this by 5, we get 2.
Now we have 2 left. Now we have to take this 2 along with the next digit 5, we get 25. If we divide 25 by 5, we get 5.
Step 3 :
By repeating this process until we get prime factors.
Hence, prime factors of 625
= 5 ⋅ 5 ⋅ 5 ⋅ 5
= 54
Example 3 :
Express 4096 as the product of prime factors
Solution :
Prime factors of 4096
= 2⋅2⋅2⋅2⋅2⋅2⋅2⋅2⋅2⋅2⋅2⋅2
= 212
Let us look into next example of "How to express a number as the product of its prime factors".
Example 4 :
Express 400 as the product of prime factors
Solution :
Prime factors of 400
= 2 ⋅ 2 ⋅ 2 ⋅ 5 ⋅ 5
= 23 52
Example 5 :
Express 144 as the product of prime factors
Solution :
Prime factors of 144
= 2 ⋅ 2 ⋅ 2 ⋅ 3 ⋅ 3
= 23 32
Example 6 :
Express 1024 as the product of prime factors
Solution :
Prime factors of 1024
= 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2
= 210
Example 7 :
Express 256 as the product of prime factors
Solution :
Prime factors of 256
= 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2
= 28
Example 8 :
Express 2025 as the product of prime factors
Solution :
Prime factors of 2025
= 5 ⋅ 5 ⋅ 3 ⋅ 3 ⋅ 3 ⋅ 3
= 52 34
Example 9 :
Express 36 as the product of prime factors
Solution :
Prime factors of 36
= 2 ⋅ 2 ⋅ 3 ⋅ 3
= 22 32
Question 10 :
Express 3136 as the product of prime factors
Solution :
Prime factors of 3136
= 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 7 ⋅ 7
= 2672