What is the answer?

What is the answer?

Auto-markingPencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about different answers to maths problems.

Question 1Change answer

a)  Natalie said the answer to 3 + 2 x 4 is 11. 
     Renata said the answer is 20. 
     Who is correct? RenataNatalie
     Explain why their answer is correct:
     

Question 1Change answer

b)  Olivia said the answer to 12 + 6 ÷ 3 – 1 is 5. 
     Kewene said the answer is 9.
     Alex said the answer is 13.
     Sue said the answer is 15.
     Who is correct? OliviaKeweneAlexSue
     Explain why their answer is correct:
     
Task administration: 
This task can be completed with pencil and paper or online (with SOME auto marking).
Level:
4
Curriculum info: 
Maths, Number and Algebra, Number Strategies
Key Competencies: 
Using language, symbols, and texts
Keywords: 
order of operations, strategies, key competencies
Description of task: 
Students demonstrate their understanding of order of operations by explaining how a correct answer is calculated.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Additive thinking, sets 7-8
Multiplicative thinking, sets 6-7
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
 

Y9 (03/1099)
a) i)
ii)		 Natalie
Any 1 of:

•   BEDMAS rule.
•   multiplication is done first.
•   addition is done last.
•   3 + (2 × 4)
•   or equivalent explanations.

 moderate
(for both correct)
b) i)
ii)		 Alex
Any 1 of:

•   BEDMAS rule.
•   division is done first.
•   addition and subtraction are done last.
•   12 + (6 ÷ 3) - 1
•   or equivalent explanations.

 difficult
(for both correct)
Diagnostic and formative information: 
  Common error Likely calculation
a) i) Renata (3 + 2) × 4 = 5 × 4 = 20
b) i) Olivia
Kewene
Sue		 (12 + 6) ÷ 3 – 1 = 6 – 1 = 5
(12 + 6) ÷ (3 – 1) = 18 ÷ 2 = 9
(12 + (6 ÷ (3 – 1)) =12 + 3 = 15

NOTE: If students get both Natalie and Alex correct but cannot explain it, it is highly likely they use BEDMAS correctly.