Transcript Factors
Multiples and
Factors
Multiples
A multiple is a number that is in the
times tables.
Multiples of 6 are
6, 12, 18, 24, 30…
Multiples of 20 are
20, 40, 60, 80, 100…
What are the multiples of…
4
4, 8, 12, 16, 20…
9
9, 18, 27, 36, 45…
30
30, 60, 90, 120, 150…
Factors
A factor is a number that divides
exactly into another number.
Factors of 6 are
1, 2, 3 and 6
Factors of 20 are
1, 2, 4, 5, 10 and 20
What are the factors of…
15
1, 3, 5, 15
28
1, 2, 4, 7, 14, 28
50
1, 2, 5, 10, 20, 25, 50
Factor exploration
Start with any number:
Write down all its
factors:
Add all but the largest:
Write down the factors
of the new number:
Add all but the largest:
… and so on …
9
1, 3, 9
1+3 = 4
1, 2, 4
1+2 = 3
1, 3
=1
9431
This is called the factor chain for 9.
Draw factor chains for these
numbers:
(a) 16 (b) 29 (c) 12 (d) 6
(e) a number of your choice
(f) Challenge: 102 (this is long!)
Play “Juniper Green”
A game for 2 players, played on a grid
like this:
1
2
3
4
5
6
7
8
9
10
11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
Play “Juniper Green”
The first player puts a counter on an
even number.
After that, players take turns,
putting a counter on either a factor
or a multiple of the last number
covered.
The first player who is unable to
cover a number loses.
Play “Juniper Green”
Show that this is a first player game
by finding the winning strategy for
the first player.
Try playing on different sized grids.
Juniper Green is named after the school where it was invented.
Thanks!
JRElse 2004