Bridge
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Approach:  Station
ACCESS
Level: Year 8
Focus: Algebraic reasoning; patterns  
Resources:
16 iceblock sticks; answer booklet
635kb
Questions/instructions:

This is a picture of a bridge.

With 3 sticks I can make this section of a bridge:
With 7 sticks I can make 3 sections of a bridge:
% responses
2009 ('05)
y4
y8
   
1. Use the sticks to make 5 sections of a bridge. Draw it here. 5 sections shown   78 (71)
 
some sections shown   9 (11)
       
2. How many sticks would you need to make 11 sections of a bridge? 23   35 (45) 
3. How did you work that out?     
clear description of general strategy   36 (30)
vague description of general strategy   21 (24)
drew the picture and counted   20 (22)
4. How many sticks would you need to make 100 sections of a bridge? 201   12 (16)
5 How did you work that out?    
clear description using equation   21 (17)
clear description using words   13 (16)
vague description of appropriate strategy   18 (20)

Total score:
 9–10
  9 (11)
7–8
  18 (14)
5–6
  27 (28)
3–4
  24 (22)
0–2  
22 (25)
Subgroup Analysis [Click on charts to enlarge] :
Year 8
Commentary:
Performance on this task was very similar in 2005 and 2009. Girls scored significantly higher than boys. Differences between Pakeha, Mäori and Pasifika students were quite small, on average, although few Pasifika students scored highly.