CHRISTMAS TREE
INVESTIGATION
YOUR CHALLENGE IS TO
INVESTIGATE THE NUMBER OF
RED LIGHTS
ON CHRISTMAS TREES OF
THEDIFFERENT
NUMBER OF
WHITE
HEIGHTS
LIGHTS
AND THE TOTAL NUMBER OF
LIGHTS
Height 3 m
Height 2 m
Height 1 m
Height 1 m
Height 2 m
Height 3 m
Height
(h)
Number of
Red Lights (r)
Number of White
Lights (w)
Total Number
of Lights (t)
1
2
3
4
5
25
h
3
0
3
1.
2.
3.
4.
5.
6.
Draw the next tree in the sequence, showing the
coloured lights.
Fill in the first 4rows of the table.
Use your drawing to fill in the fifth row.
Use the patterns in the table to predict the number of
lights on a tree 25m tall. (the height of the tree in
Trafalgar Square this year)
Can you use algebra to fill in the last row.
Make sure each of your formulas works by substituting
in a value for h that you already know the answer for.
Height 1 m
Height 2 m
Height 3 m
Height
(h)
Number of
Red Lights (r)
Number of White
Lights (w)
Total Number
of Lights (t)
1
2
3
4
5
25
h
3
0
3
3
2
5
3
4
7
3
6
9
3
8
11
3
48
13
3
2h -2
2h +1
Height 4 m