Factors, Powers And Standard Form Worksheet Page 11
ADVERTISEMENT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
2110.5
Prime factors
Keywords
prime factor
Why learn this
Objectives
You can use prime factors
C
Write a number as a product of prime
to calculate lowest
factors using index notation
common multiples and
C
Use prime factors to fi nd HCFs and LCMs
highest common factors
much more quickly.
Skills check
1 Write down all the prime numbers from the cloud.
1
21
5
39
HELP
Section 10.2
17
18
33
19
87
2 Write down a multiplication fact to show that 111
is not a prime number.
Writing a number as a product of prime factors
You can write any number as a product of prime factors.
You can use a factor tree to write a number as a product of prime factors.
60
• Split each number up into factor pairs.
• When you reach a prime number, draw
2
30
a circle around it. These are the ends of
the branches.
2
15
• The answer is the product of the prime
numbers on the branches.
3
5
60 5 2 3 2 3 3 3 5
You can write this using index notation as 2
2
3 3 3 5.
You can also use repeated division to write a number as a product of prime factors.
Divide by 2 as many times as possible.
2
60
2
30
You cannot divide 15 by 2.
3
15
Try the next prime number.
5
5
1
Divide by each prime number as many
times as possible. Stop when you reach 1.
60 5 2
2
3 3 3 5
When writing a number as a product of prime factors, write
the prime factors in order from smallest to largest.
168
Factors, powers and standard form
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education