Adding and subtracting

Adding and subtracting

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about using one method to solve story problems.
a) Read the story problems and then finish the equations.
  
  i)
Jane planted 28 carrot seeds and 14 cabbage seeds. Finish the equation to show how many seeds Jane planted altogether.
 
vertical-eg-1.png
 
  
  ii)
Mary had 74 stickers and she gave 46 to her brother. Finish the equation to show how many stickers Mary had left.
 
 vertical-eg-2.png
 
 
b)
Here is an equation.
vertical-eg-3.png
Make-up a story problem to go with this equation.
 
 
 
 
 
 
 
 
 
Task administration: 
This task is completed with pencil and paper only.
Level:
2
Curriculum info: 
Maths, Number and Algebra, Number Strategies
Keywords: 
addition, subtraction, story problems, strategies
Description of task: 
Students complete addition and subtraction story problems using the vertical algorithm.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Additive thinking, set 5
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
  Y5 (04/1999)
a) i) 42 very easy
   ii) 28 difficult
b)    Writing a story problem that involves subtraction.
NOTE: To get the mark they do not have to write "How many were left?"		 easy
Teaching and learning: 
These questions involve solving equations using the vertical algorithm (also called "standard working form").  Being taught to use an algorithm without understanding may detriment students understanding of the maths concept.  Students should have already explored a range of mental strategies for solving addition and subtraction problems involving some form of recomposition before utilising this this method.
Diagnostic and formative information: 
  Common error Likely calculation Likely reason
a) i)

    i)

 32

51

 8 + 4 = 2, 20 + 10 = 30
8 + 4 = 12, 		Ignores the 1 ten from 8 + 4 = 12.

Puts the ones in the tens column and the tens in the ones column.
a) ii) 32

30

38

 6 - 4 = 2, 70 - 40 = 30

4 - 6 = 0, 70 - 40 = 30

14 - 6 = 8, 70 - 40 = 30

 Performs 6 - 4 in ones column instead
of 14 - 6 = 8.
Treats 4 - 6 as 0 in the ones column.

Ignores renaming 74 as 614.