Is 7 a Prime or composite number?
Prime, it has two factors only, 1 and 7
42
4 x 4 = 16
What are the factors of 4?
1, 2, 4
Yes, 9 x 10 = 90
8 - 3 x 2 =
8 - 3 x 2 multiplication first
8 - 6 = 2 then subtraction
Is 15 prime or composite?
Composite, it has four factors: 1, 3, 5, 15
List the first 5 square numbers.
12 = 1 x 1 = 1
22 = 2 x 2 = 4
32 = 3 x 3 = 9
42 = 4 x 4 = 16
52 = 5 x 5 = 25
What are the factors of 12?
1,2,3,4,6,12
What are the first 5 multiples of 3?
3,6,9,12,15
4 x 2 + 3 x 2 =
4 x 2 + 3 x 2 multiplication first
8 + 3 x 2
8 + 6 = 14 then addition
List the first 5 prime numbers.
2, 3, 5, 7, 11
Write in expanded form 32 x 74
3 x 3 x 7 x 7 x 7 x 7
What is the highest common factor of 48 and 12?
48: 1,2,3,4,6,8,12,16,24,48
12: 1,2,3,4,6,12
The highest common factor is 12
What is the LCM (Lowest common multiple) of 2 and 3?
multiples of 2: 2, 4, 6, 8, 10
multiples of 3: 3, 6, 9, 12, 15
the number 6 is the lowest (smallest) common multiple
7 x (8 - 3) + 2 =
7 x (8 - 3) + 2 Brackets first
7 x 5 + 2 then multiplication
35 + 2 = 37 then addition
List the composite numbers between 11 and 22.
12,14,15,16,18,20
105
100000
Draw a factor tree and prime notation for the number 20.
What is the LCM of 4, 10, 20?
2
5 x 3 - 16 -: (8-4) =
5 x 3 - 16-:(8-4) Brackets first
5 x 3 - 16-:4 Multiplication and division next
15 - 16-:4
15 - 4 = 11 then subtraction
Is 1 a prime or composite?
Neither!
A prime number - exactly two factors, 1 and itself
A composite number - has two or more factors
62 - 32
36 - 9 = 27
Draw a factor tree and prime notation of the number 64.
Prime notation: 64 = 2 x 2 x 2 x 2 x 2 x 2 = 26
What is the LCM of 7, 21, 6?
7, 14, 21, 28, 35, 42
21,42,63,84,105
6,12,18,24,30,36,42
42 + (12 -: 3) - 5 =
42 + (12 -: 3) - 5 Brackets first
42 + 4 - 5 then indices
16 + 4 - 5 then addition/subtraction from left to right
20 - 5 = 15