Growing trees

Growing trees

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Overview
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Further Resources
This task is about working out the percentage increase of the heights of trees.
 
The heights of the trees below were measured in 2018.
 
The Pine tree measured 3 metres and the Poplar tree 4 metres.
 
 

Pine Tree 2018

Poplar Tree 2018

Question 2Change answer

a)  By 2022, the Pine Tree had grown by 60% of its 2018 height.
     How high was the tree in 2022?   metres.

Question 2Change answer

b)  By 2022, the Poplar Tree had grown by 55% of its 2018 height.  
     How high was the Poplar Tree in 2022?  metres.

Question 2Change answer

c)  In 2020, the Pine Tree was 4 metres high.
     By what percentage had it grown since 2018? %


 
Task administration: 
This task can be completed with pencil and paper or online with auto-marking.
Level:
5
Curriculum info: 
Maths, Number and Algebra, Number Strategies
Keywords: 
percentages, increase
Description of task: 
Students work out the height of trees which have grown by different percentages, and work out the percentage growth from two given heights.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Multiplicative thinking, sets 8-9
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
 

Y10 (10/1998)
a) 4.8 moderate
b) 6.2 moderate
c) 33.3 [Accept 33, 33.33 etc.] difficult
Diagnostic and formative information: 
  Common error Likely calculation Likely reason
c) 25 (4 - 3) ÷ 4 × 100 Percentage growth of final (2020) height rather than initial (2018) height.
c) 133 4/3 × 100 Percentage of initial height rather than percentage growth.