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Investigating
Factors of numbers
Investigate the factors of the following numbers
No.
Factors
Prime
No.
1
11
2
12
3
13
4
14
5
15
6
16
7
17
8
18
9
19
10
20
Factors
Prime
No.
Factors
Prime
No.
Factors
Prime
1
1
No
11
1, 11
Yes
2
1, 2
Yes
12
1, 2, 3, 4, 6, 12
No
3
4
Prime numbers are
13 1, 13
1, 3
Yes
numbers that have exactly
1, 2,7, 14
1, 2, 4
14
No
two different factors
Yes
No
5
1, 5
6
1, 2, 3, 6
7
1, 7
8
1, 2, 4, 8
No
18
1, 2, 3, 6, 9, 18
No
9
1, 3, 9
No
19
1, 19
Yes
10
1, 2, 5, 10
No
20
1, 2, 4, 5, 10, 20 No
Yes
15
1, 3, 5, 15
( no more / no 16less)
1, 2, 4,8,16
No
They have
Yes 1 and themselves
17
1, 17
No
No
Yes
Prime numbers are numbers that have exactly two different factors
( no more / no less) They have 1 and themselves
The first fifteen Prime numbers are
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47
Prime factors of a number
Find the factors of a number and say which are prime
e.g1 Find the prime factors of(i) 10 and (ii) 16
10
Prime factors of 10
1 x 10 are 2 and 5
2x5
16
1 x 16
2x8
4x4
`Prime factor of 16 is 2