1. The second lesson in a series of work on level 6+ maths
KS2 Skills
Factor trees starter M A T H S
MIXED STARTER M A T H S
MIXED STARTER
Write the smallest multiple of three that is bigger than one hundred
Put the squares above in size order (smallest to largest). Explain your solution.
What number is five cubed?
The second lesson in a series of work on level 6+ maths
Find the value of a, b and c from the diagram
LO: To construct prime factor trees

2. The second lesson in a series of work on level 6+ maths
Number theory:
Factor trees
14/11/2018
Core: will be able to identify and use prime numbers.
Challenge: will be able to use factor trees to express a number as a product of its primes
Aspire: to use known facts
Vivo Star: Display a high level of understanding including
how all values can be expressed using prime factors.
Keywords: Factor, Prime, Product and Indices
The second lesson in a series of work on level 6+ maths
LO: To construct prime factor trees

3. The second lesson in a series of work on level 6+ maths
Powers M A T H S
ACQUIRE FLUENCY 12 22 32 42 52 62 72 82 92
102 13 23 33 43 53
The second lesson in a series of work on level 6+ maths
Can you find all the factors of 120 which are also prime numbers?
Calculate the following
(1) 33 x 22
(2) 12 x 3 x 52
(3) 3 x 22 x 7
(4) 3 x 23 x 5
LO: To construct prime factor trees

4. The second lesson in a series of work on level 6+ maths
Prime factor trees M A T H S
TALK ABOUT IT
To find the prime factorisation of a number is to express it as a product of prime numbers. ?
30=2×3×5 12= 2 2 ×3 ? ?
120
= 2 3 ×3×5
We can use a ‘tree’ to help us with the working.
For each number, find two numbers the multiply to give it.
The second lesson in a series of work on level 6+ maths 20 6 4 5 2 3
If you get to a prime, we can’t branch out further, so we have a ‘leaf’. It’s helpful to circle the leaves. 2 2
LO: To construct prime factor trees

5. The second lesson in a series of work on level 6+ maths
Factor trees, factors and roots M A T H S
HAVE A GO
These numbers have been written as a product of primes. Find each number
By drawing a tree of otherwise, find prime factorisations (in index form) for the following numbers.
28= 𝟐 𝟐 ×𝟕 75=𝟑× 𝟓 𝟐 1000= 𝟐 𝟑 × 𝟓 𝟑 378=𝟐× 𝟑 𝟑 ×𝟕 396= 𝟐 𝟐 × 𝟑 𝟐 ×𝟏𝟏 1755= 𝟑 𝟐 × 𝟓 𝟐 ×𝟏𝟑 432= 𝟐 𝟒 × 𝟑 𝟑 ?
(1) 23 x 32
(2) 22 x 5 x 72
(3) 3 x 52 x 7
(4) 2 x 33 x 5 ? ? ?
The second lesson in a series of work on level 6+ maths ? ? ?
What are the factors of 2 5 ?
𝟏, 𝟐,𝟒,𝟖,𝟏𝟔,𝟑𝟐
Write 36 as a product of its primes.
Explain why 36 is a square number and use your prime factorisation to square root 36. ?
LO: To construct prime factor trees

6. The second lesson in a series of work on level 6+ maths
Known facts M A T H S
SUM IT UP 2 1
225 =
2 x 3 x 5 = 2 2 2
Given that
450 = 2 x 3 x 5 2 2
The second lesson in a series of work on level 6+ maths 4
Extension:
Explain why 900 is a square number and find it’s square root 3
150 =
2 x 3 x 5 = 2 2 3
LO: To construct prime factor trees